Friday, August 19, 2016

Summery Pseudo Stew of Zucchini, Tomatillos and Corn

Valentine (ca. 1945) from Deseronto Archives
Summer produce won't be around much longer, so I've been eating summer specialties as much as possible. Last Sunday, my focus was zucchini, tomatillos and sweet corn, which I combined in a "pseudo stew." I'm calling it a "pseudo stew" because it was too liquid to eat on a plate, not thin enough to be a soup, but didn't quite feel like a stew.  I ate it with rice that week — I suspect that it could be a good filling for tacos, burritos, or quesadillas.

These days my cooking is a little unfocused, so it doesn't take much to get me moving into a certain direction.  The inspirations for the pseudo stew were a tweet from Simply Recipes about sauteed zucchini; a new carbon steel skillet that I purchased from Food52 that is naturally non-stick and loves high heat; and summer produce.

In the end, my pseudo stew came from the adaptation and merging of three recipes:

The basic idea was to make three simple preparations and combine them for the final dish: 1) broil tomatillos until soft, then puree with chipotle puree; 2) sear zucchini (adding garlic at the end); 3) pan roast sweet corn.

To be sure, a similar pseudo stew could be prepared with much less effort: simmer tomatillos in a little bit of water until soft, then puree with immersion blender; add zucchini, corn, chipotle puree, onions, garlic, and cook until the vegetables are tender; garnish and serve. This would certainly work, but the flavors wouldn't be as complex.

For the zucchini and corn, you'll get best results with a pan that can get very hot and is relatively non-stick (like carbon steel, a wok, or a cast iron skillet). The goal is to have a good amount of color on the vegetables.

Recipe:  Pseudo Stew with Zucchini, Tomatillos and Corn

6-8 small to medium zucchini
2 cloves garlic
3 ears sweet corn
2-3 cups (480-720 mL) whole tomatillos (about 15 medium)
1 t. (5 mL) or more chipotle chile puree (see note below)
1 t. (5 mL) salt
Chopped cilantro leaves
Toasted pumpkin seeds (optional)
Crumbled queso fresco or queso anejo (optional)

Prepare the tomatillos:  Turn on the broiler.  Peel the paper husks off of the tomatillos, wash them, and put them in a single layer in a broil-safe baking pan (use one with sides since there will be juices running).  Place under broiler. Broil until blackened on one side, then turn (different sized tomatillos cook at different rates, so you might need to turn them at different times, and remove them as they finish cooking).  Puree the chipotle chile puree and roasted tomatillos (and any juice that was exuded) in a blender or with an immersion blender.  Put the puree into bowl that will be large enough to hold the zucchini cooked in the next step.  Set aside.

Prepare the zucchini:  Choose a pan that can hold all of the zucchini, corn, and tomatillo puree, ideally one that can be used over high heat.  Cut the zucchini into bite-sized pieces — cut small zucchini in half lengthwise and cut into slices; cut larger ones in quarters lengthwise and cut into slices.  Mince the garlic.  Heat a pan over medium-high heat.  Add 1-2 tablespoons of oil.  Add the zucchini and saute, stirring frequently, until some of the pieces are browned, a few minutes.  Add the garlic, stir, cook for about 30 seconds. Scrape the cooked zucchini and garlic into the bowl with the tomatillo puree.  Add 1 teaspoon salt.  Stir to combine.

Prepare the corn: Clean the pan used to prepare the zucchini (or pull out another clean one).  Cut the kernels off the corn cobs, being sure to scrape the cobs with the back of the knife to extract as much corn as possible.  Heat a pan over medium-high heat.  Add 1-2 tablespoons of oil.  Add the corn and cook, stirring occasionally for a few minutes until the corn is cooked and browned in places.  Turn down the heat. 

Assemble:  Add the zucchini-tomatillo mixture to the corn.  Stir well, then simmer for a few minutes to meld the flavors. Adjust the salt as needed.

Serve and Garnish:  Serve with rice or tortillas.  Garnish with chopped cilantro, toasted pumpkin seeds and crumbled cheese (like queso fresco, queso anejo, or sharp cheddar).

Variations:  Pan-roast a few cloves of garlic, mince, and add to the tomatillos before pureeing. Saute some sliced onions with the zucchini.  Add minced raw or pan-roasted green chiles.  Add diced roasted poblano chilies.

Note: to make chipotle chile puree, buy a can of chipotle chiles in adobo sauce, open it, and put the contents in a blender or food processor. Process until smooth. For long term storage, wrap and freeze. The puree stays soft enough in the freezer so that you can easily slice off what you need. If you also keep tomato paste in the freezer, be sure to label the chipotle puree so you don't mix up tomato paste and chile puree.

Image Credits
Corn & squash valentine (ca. 1945) from the Deseronto Archives's Flickr collection, no known copyright restrictions. Photos of the evolution of fresh tomatillos to salsa by the author. 

Random link from the archive: Recipe: Flourless chocolate-almond cake

Sunday, August 14, 2016

Keeping an Open Mind about Insects and Other Sustainable Foods

One night, the beef tongues in Chef Cesar Cienfuegos' kitchen started speaking to him. They told him "There must be a better way, you need to start thinking differently."

It was a special night in the University of California, Davis (UCD) dining halls — one of the nights when the kitchens prepare an unusual entree that is featured in every dining hall. That night it was beef tongue ramen, with Dining Services preparing enough so that 3,500 bowls could be ladled out across campus. It required over 200 tongues (about 650 pounds in total), a quantity that led Cienfuegos to think, that just "one night, one meal, one recipe" uses so much animal flesh, there must be alternatives.

This story launched a presentation by Cienfuegos and co-presenter Ben Thomas (from the Community Alliance with Family Farming, who also has worked with UCD Dining Services) at the International Food Blogger Conference (IFBC) entitled "Why Insects are the Next Super Food that will Save the Planet - A Chef's Perspective".

Sustainability Concepts
Although the headline topic was insects, Cienfuegos and Thomas wanted to explore a range of food sustainability ideas that included these four concepts:
  • By products and "waste": An example of this is flour made from the remnants from wine grape pressing (the Whole Vine company is a nearby producer)
  • Low impact ingredients: insects are a prime example, as life cycle analysis shows that they produce protein with relatively low greenhouse gas emission and water use
  • Underutilized ingredients: "trash fish" (less marketed fish often caught with more desirable fish) and nopales (cactus paddles, which grow readily with little water in California and other arid places)
  • Positive impact ingredients: edible nitrogen fixing plants, edible cover crops like burdock (another example would be farmed oysters, which clean the water as they grow)

Sunday, August 07, 2016

Follow my blog with Bloglovin

Follow my blog with Bloglovin

With the demise of so many blog reading and following tools (Google Reader, Bloglines, too many RSS readers to count), I'm going to try Bloglovin.

Growing Belgian Endive is "A Really Wacky Process" - Touring California Endive Farms

Spotlight on endive in the forcing room
(Disclosure: this farm tour was a pre-conference excursion arranged by the International Food Bloggers Conference. Although I paid to go on the excursion, it is possible that California Endive or the California Pear Board provided some subsidies to reduce participants' costs.)

You might have spotted Belgian endive in your local supermarket and thought "yet another salad green, nothing special." But you'd be wrong. Belgian endive is an amazing vegetable that requires significant agricultural ingenuity to grow.

I learned about Belgian endive on an excursion to California Endive Farms in Rio Vista, California, organized by the International Food Blogger Conference (IFBC). The bus ride from Sacramento to Rio Vista was enlivened by an engaging explanation of endive by Rich Collins, the founder of California Endive Farms (who provided the memorable quotes that make up the title and subheadings in this post).

Collins started with a pronunciation lesson: the plant we were going to see must be pronounced "ahn-deev." The other pronunciation, "n-dive," is used for field greens like curly endive and frisee, and it is important to keep them separate. A mnemonic that came to me today is to think "diva" when speaking of Belgian endive ("ahn-diva"):  it requires a lot of pampering, but in the end you get something great. The tour group took the pronunciation guide to heart, and for the rest of the conference anyone who referred to Belgian endive as "n-dive" was quickly corrected — including one of the speakers, who was demonstrating a recipe that involved placing a dollop of chicken salad onto an endive leaf and said "n-dive." 

Growing Endive is "A Really Wacky Process"
In the mid-19th century, a Belgian farmer was drying some chicory roots in his cellar over the winter so he could roast them and use them as a coffee substitute. When spring brought warmer temperatures, he discovered that some of the roots had sprouted an ellipsoidal head of leaves. He tasted them, liked them, and realized that this process could be controlled. And so a new food product was created.  These days, there are numerous producers in Europe, but California Endive Farms is the only producer in the United States.

Growing endive is a little like growing mushrooms, but instead of starting with spores, you start with a root (to learn about mushroom farming, check out my post about a tour of Far West Fungi). Growing the root is the most 'normal' part of the process: farmers sow chicory seeds in the field (about 50 varieties are commercially available, California Endive grows 5-8 each year). Fortunately for endive farmers, chicory is a vigorous grower (Collins called it a weed, and noted that it grows all over the region), so it is not too difficult to produce the root.

After around 5 months, fields are filled with sturdy plants held in place by a mature root that is about the size of 12 ounce bottle of beer. The harvest crew digs up each root, cuts off the leaves (about 16-20" in length), removes thin tendrils, and puts them into boxes. Around 40 million roots are produced per year in several fields.  The greens are left in the field to compost in place, or might be disked into the soil to speed the process.
At the California Endive facility, the root is trimmed again with more care (it is important to have just the right amount of green top on the root and have it be even) and then placed into cold storage, where the root hibernates at a temperature around freezing (our visit to the cold storage room was quite bracing after the 100 F heat of Rio Vista). The entire season's harvest of roots are placed in cold storage and held until they are needed, thus allowing year-round production of the product so when the market needs endive, roots are ready to go.

Roots ready for trimming (left), roots and frost in the cold storage room (right)

A "wall of endive" in the forcing room
The next step is mushroom-like. Roots are pulled from cold storage, placed in growing medium trays, and moved to a dark, cool, humid room where a flow of water and nutrients revives the root — darkness is necessary to create a "blanched" endive that is as pale as possible since green leaves are more bitter. One bud forms on each root and within about 3 weeks the endive is market-ready. It seems simple, but our tour guide was emphatic that the forcing room is "more of an art than a science" — getting the right temperature, water flow, nutritional composition, and so forth can be challenging.

When the buds have grown to market size, the forklifts roll in and carry the trays to the neighboring packing house, where the endives are removed from the roots and packed and shipped (two of the biggest customers are Trader Joe's and Whole Foods).

On a normal packing day, the crew handles 25-30 tons of roots, creating a major waste stream. Looking at those chicory roots, one might think: "Why not sell them to New Orleans coffee companies like Cafe du Monde for their famous chicory-infused coffee?" A good idea, but it wouldn't last long: with the current use of chicory in U.S. coffee, it would take less than one day for California Endive to meet the annual demand. So, like many other agricultural wastes (okara from tofu making, almond husks, etc.), they are sold as cattle feed (and someday might be part of a feed-blend for mini-livestock, i.e., insects?).

I made a flowchart that shows the process:

"When you are eating endive, you are eating chicory"
One of the quirks of Belgian endive is that it is not a "true endive" but is actually a chicory.  The true endives are escarole, frisee and curly endive (which is sometimes marketed as "chicory" or "curly chicory").  In other words, vegetable names can be confusing.

Collins didn't tell us why the word endive is used in the U.S. instead of chicory. I would guess that that the early importers borrowed the French name since French cooking had such massive influence in the late 1800s and early 1900s. The vegetable goes by many names around Europe, as Elizabeth Schneider details in her invaluable Vegetables from Amaranth to Zucchini: the British call it Belgian or Brussels chicory, French-speaking Belgians call it chicon, Flemish-speaking Belgians call it witloof ("white leaf").  Wikipedia says that the Dutch also call it witloof and a German food glossary suggests that Germans call it ChicorĂ©e.

Eating and Cooking Endive
At lunch under a tree at the Stillwater Orchards pear farm near Courtland, we enjoyed two endive salads, allowing me to eat more than the American per capita average of 4 leaves per year* via a "red, white, and blue salad" of red endive, white endive, blue cheese and pears (a similar recipe is on the California Endive blog), and a grilled endive salad (which reminded me a little of seared radicchio).

Schneider's book has some clever quips about endive: "Happily, Belgian endive is far easier to cook, eat, and enjoy than to cultivate or refer to correctly in print," and "whatever method [of cooking] you choose, Belgian endive is likely to respond kindly." She follows these quips with tips on preparation, several pages of recipes, and a "Pros Propose" section with suggestions from professionals like Joyce Goldstein, Barbara Kafka, and Yamuna Devi.  You'll also find plenty of recipes at megasites like Epicurious and NYT Cooking.

Other Posts about the Endive Tour From IFBC Attendees (and Press)

* After saying that his "biggest competitor is ignorance," Collins noted that the average annual per capital consumption of Belgian endive in the U.S. is about 4 leaves. In France, it is 8-9 pounds.

Random link from the archive: 7 Year Bread (pumpkin pecan spiral)

Sunday, July 17, 2016

Recipe: Simple Macaroni and Cheese

Almost exactly one year ago, there was some commotion* in my tiny corner of the Twitterverse about a New York Times recipe from Julia Moskin for macaroni and cheese. There are a zillion mac and cheese recipes, so what caused the commotion? Uncooked macaroni. The recipe calls for uncooked macaroni to be mixed with milk, cheese seasonings, and blended cottage cheese, and then the whole thing baked for 60 minutes. Several in the Twitter commotion were highly skeptical, including me. But we were foolish to doubt the New York Times cooking team: the recipe was a success and has become a 'go to' recipe for me.  And also is a lot easier to make than my previous favorite macaroni and cheese (from the now-gone Paper Palate blog).

The recipe wasn't quite right for me as originally written, so I have been making changes:  four about ingredients, two about methods.

  1. Cut it down: The first modification happened before I even made the first batch: I thought that 1 pound of cheddar cheese was too much, so I cut it in half. 
  2. Frozen: Next, I tried freezing the cottage cheese. The recipe calls for 8 ounces of cottage cheese and I buy it in 16 ounce containers, so I froze the extra 8 ounces and used it in a batch a few weeks later (after defrosting). It was fine — the freeze / thaw cycle didn't have any negative effects on the dish.
  3. The whole story: Hearing so much about whole grains, it was worth trying a whole wheat pasta. The pasta cooked properly and made the flavors a bit more robust.
  4. Choppin' lots of broccoli: The final ingredient tweak has been to add some chopped broccoli halfway through the baking time (when the mixture is gently stirred). The broccoli cooks nicely and adds nutrients and flavors.
  5. Simpler combine: The original recipe calls for the milk, seasonings, and cottage cheese to be blended together, and then the mixture combined with the pasta and grated cheese in a large bowl. Instead of mixing everything in a bowl, why not pour the pasta and grated cheese into the blender jar and then mix it by hand? It's slightly challenging to get a uniform mix in the blender jar, but that can be corrected in the baking dish. (Of course, an immersion blender could also be used in a mixing bowl to blend the cottage cheese, milk and seasonings, and then the pasta added to that bowl.)
  6. One tool, two jobs: A few weeks ago, I had a question while I was washing dishes after making the recipe: Could I use a food processor to grate the cheese and blend the ingredients, thereby cutting the 'wash list' by one?  The answer is yes. Step 1: use the food processor's grater disk to grate the cheese. Remove the cheese and put it on the plate you are going to use for dining to save a dish. Step 2: switch to the blade and process the cottage cheese, milk, and seasonings. Step 3: add the dry pasta and grated cheese to the bowl and mix everything together by hand. Step 4: pour into the prepared pan. 

Saturday, July 09, 2016

Tracking Retail Cricket Flour Prices

Person pointing at a chart (from the Internet Archive)
I have been following the field of entomophagy (insects as food) for a little while: watching the news, occasionally writing news roundups or more detailed pieces (see notes section).  So I have been wondering, as news coverage has increased, new products are launched, and companies start scaling up their insect-rearing operations, what is happening to retail prices?  

In early 2015, I started recording the retail price of 100% pure cricket flour at a handful of on-line stores (shipping costs were not considered).  The results of these surveys are shown in the chart below. 

Suppliers' prices vary significantly, with a spread of about 20-30% from the average. The retail price has been relatively stable over the period of study — the average retail price of pure cricket flour is about $40 per pound. These are not terribly surprising results.  This is a newly developing market, and it takes time to scale up and optimize — the teams building insect farming infrastructure need time to acquire land and farming space, develop more efficient farming techniques, increase processing capacity, and build distribution networks.  (And, of course, they'll need many more customers.)

My price survey has some deficiencies. The first is that it considers retail prices, while the major action in cricket flour is probably at the wholesale level (e.g., sales to manufacturers like Bitty Foods and Exo) and so it would be better to be tracking wholesale prices. These aren't as readily available, however.  The second is about shipping: some companies offer free shipping for orders above certain amounts, others charge for shipping on all orders. For example, in the June 2016 survey, the low-price option charges $11 for shipping, the high-price option includes shipping, one company sets its free shipping limit below the price of a pound of cricket flour, another sets it above the price of a pound.

Livestock prices from USDA Economic Research Service
If the industry grows significantly, real food data experts might step in.  One group of food data experts is the staff of the USDA's Economic Research Service, which has built an amazing collection of data and reports about agricultural products and markets — data products like the aquaculture dataset "Statistics on domestically grown catfish and trout and U.S. imports and exports of fish and shellfish that may be products of aquaculture, such as salmon, shrimp, and oysters"; or monthly reports like "Monthly average price values at the farm, wholesale, and retail stages for selected cuts of beef, pork, and broilers;" or charts like the one on the right. I didn't find anything about insects as food at the Economic Research Service, but perhaps in the future the Service will be tracking the industry, publishing a monthly "Insect Outlook," and compiling data about "Monthly average price values at the farm, wholesale, and retail stages for selected species of edible insects." 

My previously posted pieces about insects as food:
If you want to closely follow what is happening in the entomophagy movement, three great places to start are the Twitter feeds of @AnaCDay, @littleherds, and @4EntoFOOD (to name a few of the good ones that are out there).  Ana C. Day also runs an entomophagy news collection service on the service.

Image Credits
Person pointing at a chart is from page 752 of "Illinois Agricultural Association record [microform]" (January 1944- December 1949) from Internet Archive's Flickr collection, no known copyright restrictions.  Agricultural price chart is from the USDA Economic Research Service, not subject to copyright (U.S. Government product).

Random link from the archive: Annatto Seeds – An Ancient Dye and Flavoring with a Global Reach (insects are another source of dye, notably cochineal, which caused some trouble for Starbucks a few years ago)

Sunday, June 19, 2016

A Visit to a Tofu Factory

As I was writing the post about savory baked tofu, I remembered a piece I wrote for the Ethicurean about a visit to a local tofu factory (original post URL).  With the Ethicurean archives being inaccessible, I thought it would be worthwhile to update the original piece and post it here. My visit was in 2010, so it is possible that there have been some changes to their procedures, but the piece still gives a good overview of tofu making.

Farmers markets are far more than a source of good food and a place to build a stronger community. They can also serve as incubators for food businesses — places where entrepreneurs can try selling prepared foods on a small scale or where experienced market participants can try out new products or recipes.*

One of the many food businesses incubated by farmers markets is Hodo Soy Beanery, a tofu-making company based in Oakland, California.  The company was started in 2004 because the founders wanted better tofu than they could find at local stores, and figured that many others were also looking better tofu, so they started making their own.

The initial launch pad was a single farmers market.  The next steps were additional markets and multiple restaurant accounts, like San Francisco's Slanted Door.  In recent years, they have been selling in many supermarkets and have landed some major accounts (like supplying tofu to Chipotle to use in their sofritas offering). Alas, this success led to their withdrawal from farmers markets — the markets weren't worth the effort.

Soybean cooking equipment at Hodo Soy Beanery
Soybean cooking equipment
Several years ago I toured the Oakland facility. It reminded me of a cheese factory, with stainless steel vats, tanks, and molds, but without the yeasty, cultured aroma that you find in a cheese factory. The equipment similarity is not surprising, because tofu is basically a soy cheese made by heating, curdling, and pressing. Although one could probably adapt some of the cheese equipment for tofu, the equipment in Hodo's plant was designed and built in Asia specifically for soy milk and tofu making.

Dry soybeans are the starting ingredient for all of Hodo's products. The beans are soaked in water for several hours to rehydrate them, then cooked under pressure. The cooked beans are finely ground and passed through two levels of filtration to separate the solids from the liquid. The resulting liquid is soy milk; the solids are generally known by the Japanese word okara. The soy milk can be bottled and sold or made into tofu or yuba.  The okara is generally sold to livestock farmers (for much more about okara, see this post on Mental Masala).

Tofu making equipment at Hodo Soy Beanery
Forming large blocks of tofu
To make medium or firm tofu, the hot soy milk is transferred to a vat. Coagulant is added to start the curdling process; in Hodo's case, it's calcium sulfate, a naturally occurring mineral that has been used by the Chinese for centuries. The mixture is stirred, allowed to curdle, and then the curdled mixture is poured into a cloth-lined porous mold. The whey goes down the drain.**

The curds are pressed to remove excess water using a weight appropriate for the grade — medium tofu gets one weight, while the firm tofu goes into a special machine for some serious squeezing. After the pressing is complete, the tofu is cut into blocks and transferred to cool water baths for storage until it is packaged for sale or transferred to the in-house kitchen to be made into one of Hodo's prepared foods, like edamame tofu salad or spicy braised tofu.

The process for silken tofu is slightly different because it is so fragile: soy milk and the coagulant are mixed in the consumer containers (e.g., pint-sized plastic tubs) and allowed to naturally set without any pressure. This process creates a smooth, delicate texture.

Photograph of yuba making at Hodo Soy Beanery
Hanging sheets of yuba
Yuba is the most distinctive product made by Hodo. It's a thin, rippled, pale-yellow, somewhat elastic sheet that is composed of soy proteins and lipids. To make the sheets, an array of shallow containers are filled with soy milk and steam heat is applied to the bottom.  A skin forms on the cooled upper surface. After a short time, the skin can be removed by hand and hung to dry before packaging.

Yuba is subtle and delicate: some call it the "sashimi of tofu," and it was the inspiration for a piece in the New York Times Magazine by San Francisco chef Daniel Patterson (Coi, LocaL and other Bay Area restaurants).  It is versatile, serving as a wrapper for a savory filling, as a pasta analogue, and as an addition to soups or salads, to name a few uses.

Although I'd love to see Hodo branch into other soy products like tempeh or soy sauce, they would need to make those items in a different facility because the organisms that drive the tempeh and soy sauce fermentation process could colonize the factory and cause all sorts of trouble for the soy milk and tofu production lines.

Further reading about tofu and the Hodo Soy Beanery:
*  Has anyone compiled a list of food companies that were incubated at farmers markets?  Another Bay Area incubation success that I can think of off the top of my head is Tacolicious, a group of San Francisco Bay Area restaurants that got their start as a taco vendor at the Ferry Plaza Farmers Market. 
** Okara and the whey from the tofu-making process are apparently useful as green cleaning agents. Tofu Cookery by Fusako Holthaus notes that okara can be used to polish floors and woodwork. The book recommends wrapping okara in a cloth and applying vigorously to a surface, but is short on details — should the okara be dry or moist? What kind of cloth is recommended? The Book of Tofu by William Shurtleff and Akiko Aoyagi notes that the whey can be used as a soap, and that they have heard of tofu shops using the whey to clean tofu-making implements and workers' hands.

Random link from the archive: Making up for travel by buying political activism instead of 'offsets'

Sunday, June 12, 2016

Recipe: Baked Tofu

Making tofu at Hodo Soy Beanery
Making tofu at Hodo Soy Beanery (2010)
One of my favorite things to cook is also one of the most unphotogenic dishes I know: the savory baked tofu from Sundays at Moosewood Restaurant*. Although it has a monotone and bland brown hue, its taste is much more exciting: tofu's subtle flavor in the background,  and a foreground of soy sauce, ginger, garlic, vinegar and sesame oil.** 

The dish is quite easy to make:  put the sauce ingredients into a baking dish, slice some tofu, add it to the pan, and bake.  Sometimes I add sliced carrot or wedges of Satsuma sweet potato (a variety from Japan) to the pan and let the vegetables roast along with the tofu.  Although it seems like a good idea at the time, it is rarely successful because the baking times are mismatched.  

You could probably just set the tofu block into the baking pan and wind up with an OK result, but you'll get much better flavor if there is more exposed surface area to roast and absorb the sauce.

As I thought about describing how I like to slice the tofu, my descriptions soon became hopelessly confusing, so I made simple drawing to help explain.  The drawing below roughly replicates the dimensions of a standard piece of tofu, with the primary dimensions represented by 1, 2 and 3***.  I prefer the pieces of tofu to be relatively thin, so I like to make one cut on side 1, two cuts on side 2, and two cuts on side 3 to give 18 rectangles. Of course, more pieces means more turning. 

Recipe:  Baked Tofu
Adapted from Sundays at Moosewood Restaurant

16 ounces (453 g) tofu, firm or extra firm, cut into rectangles, triangles or other shapes
3 T (45 mL) soy sauce
1.5 T (22.5 mL) rice vinegar
1.5 T (22.5 mL) sake or rice wine
1 garlic clove, minced or pressed
3 t (15 mL) grated ginger
4 T (60 mL) water
3 t (15 mL) sugar
1 T (15 mL) toasted sesame oil

Preheat oven to 375 F (190 C).

Combine all of the ingredients except the tofu in a shallow baking dish [8" x 8" or larger (20 cm x 20 cm)].  Add the tofu pieces and turn a few times to coat the surface.  Bake for 30-40 minutes, turning the pieces every 10 minutes.  There is no fixed point when the dish is "done," so you can decide that it is done based on how much sauce is left, the color of the tofu, or that it is time to eat.  

* Some other great recipes in Sundays at Moosewood Restaurant include Groundnut Stew, Capetown Fruit and Vegetable Curry, Beurek with Parsley-Cheese Filling, Berbere (a spice mixture), Niter Kebbeh (spiced clarified butter), and the two W'ets (Ethiopian stews that use the Niter Kebbeh).
** Good, but not good enough or original enough to submit to Food52's best tofu recipe contest
*** Most blocks of tofu seem to be the same size.  How long ago was that dimension chosen, and how was it chosen?  Might there be a centuries-old Chinese or Japanese specification that was adopted by makers in the U.S.?

Random link from the archive: Tempura at Ten-Ichi