What it is: "Soybean curd" is made by heating soymilk and a curdling agent in a process similar to dairy cheesemaking. Allowed to stand and thicken, the curds form silken tofu. When stirred and separated from the whey, the pressed curds, with their spongier texture, are known as "regular" tofu. The longer the pressing, the firmer and denser the tofu—soft, firm or extra-firm.
What to do with it: Silken tofu is delicate and custardlike, perfect for pureéing and using in dressings, smoothies, sauces or floating in delicate soups. Extra-firm tofu is ideal for stir-fries, sautés and grilling, while the soft variety makes a good substitute for ricotta in Italian dishes or for eggs in quiches. Firm tofu is a good all-purpose choice. Tofu will last 5 to 7 days after opening. Store in a loosely sealed container of water in the refrigerator, changing the water daily.