Loosely adapted from Practical Japanese Cooking by Shizuo Tsuji and Koichiro Hata.
- 1 block regular "cotton" tofu
- 2 cups stock: meat, dashi, or vegetable
- 1/4 cup dark soy sauce
- 1/4 cup sake or rice wine
- 1/4 cup mirin or 2 tablespoons sugar
- Thinly sliced green onions, to garnish
The night before, wrap the block of tofu in cheesecloth and freeze for at least six hours, or up to 2 weeks. Frozen, the tofu will be yellow and leathery in appearance.
When you are ready to cook, run the block of tofu under hot water to remove the cheesecloth, which will have adhered to the surface of the tofu. Bring a large pot of water to boil and drop in the tofu. Boil for 15 minutes, or until the entire block of tofu is softened.
Cut the tofu into 1-inch squares and place into a saucepan along with the rest of the simmering ingredients (stock, soy sauce, sake, and mirin). Over medium-low heat, simmer for at least 25 minutes, or until the tofu has fully absorbed all but 1 tablespoon of the liquid. (Variation: If you are braising cubes of meat in a soy sauce dish, toss the cubes of tofu into the pot during the last half hour of braising.)