Walnut Tofu (くるみ豆腐, Kurumi-dofu)

Ingredients

Equipment Needed

• •Suribachi and surikogi, or a blender
• •Nagashikan rectangular mold, or a small loaf pan
• •Fine-mesh strainer
• •Heavy saucepan and wooden spatula

Instructions

1. 1

   Soak the dashi

   Wipe the konbu with a damp cloth, but don't wash it. Put the konbu, dried shiitake, and cold water in a pot and soak for at least 30 minutes, or overnight in the refrigerator if you have the time. Cold soaking draws out sweetness from the shiitake and lets the konbu give itself up gently.

   That pale bloom on good konbu isn't dirt. It is part of the flavor, and rinsing it away is a very efficient way to make thin dashi.
2. 2

   Draw the dashi

   Set the pot over low heat and bring it slowly to the point where the water trembles and small bubbles climb the sides. Lift out the konbu before the water boils, then keep the shiitake in the hot liquid for 10 minutes off the heat. Strain. You need 2 cups dashi for the tofu and 2 tablespoons for the sauce; add a little cold water if you are short.

   Boiling konbu gives the stock a bitter, slick edge. The rule is simple because the reason is simple: protect the clean taste.
3. 3

   Prepare the walnuts

   Pour boiling water over the walnuts and leave them for 2 minutes. Drain, rub off any loose skins with a towel, then warm the walnuts in a dry pan over low heat for 3 to 4 minutes, just until fragrant. The skins carry bitterness, and a brief warming wakes the oil without turning the dish into roasted-nut paste.

4. 4

   Grind the paste

   Grind the walnuts in a suribachi with a surikogi until they become a smooth paste, adding spoonfuls of the measured 2 cups dashi as needed to loosen them. A blender works too: blend the walnuts with about 1 cup of the dashi until very smooth. Pass the mixture through a fine sieve if you want a silkier set. Large bits interrupt the kuzu gel, and the finished block will tell on you politely.

5. 5

   Dissolve the kuzu

   Crush the hon-kuzu into a fine powder, then whisk it with the remaining cold dashi until no hard specks remain. Add the walnut paste, 1 tablespoon mirin, and salt, and whisk again. Kuzu must meet cold liquid first; hot liquid seals the outside of each lump and leaves dry starch trapped inside.

6. 6

   Cook until glossy

   Pour the mixture into a heavy saucepan and set it over medium-low heat. Stir constantly with a wooden spatula, scraping the bottom and corners. It will look thin, then thicken suddenly, then become heavy and glossy. Keep stirring 8 to 10 minutes after it thickens, lowering the heat if it threatens to scorch. It is ready when it gathers as one mass and pulls cleanly from the pan.

   This is the deciding step. Undercooked kuzu tastes chalky and sets weakly; fully cooked kuzu turns clear, elastic, and clean on the tongue.
7. 7

   Mold and chill

   Rinse a nagashikan, small loaf pan, or four small cups with water and leave them wet. Scrape in the hot walnut mixture, smooth the top with a wet spatula, and tap the mold once or twice to settle it. Press a piece of wrap or parchment directly on the surface and let it cool, then chill for at least 3 hours. The wet mold helps release the tofu, and covering the surface keeps a skin from forming.

8. 8

   Sauce and serve

   Warm the reserved 2 tablespoons dashi with the usukuchi shōyu and 1 teaspoon mirin just until the mirin's raw edge softens, then cool it. Unmold the kurumi-dofu and cut it with a wet knife into four squares or eight small blocks. Set one portion in each dish, spoon a little sauce beside it, and finish with wasabi and, in winter, a fine strip of yuzu peel. Sauce beside, not over. Nothing hidden.

Chef Tips

• •Taste one walnut before you start. It should be sweet and clean, never sharp or paint-like. Walnut oil turns rancid easily, and no amount of shōyu will rescue it.
• •Buy hon-kuzu if you can, usually sold in pale chunks or coarse powder. Potato starch can thicken a sauce, but it won't give this dish the same quiet spring and clean break.
• •Keep the heat modest once the kuzu thickens. A fierce flame scorches the walnut oil at the bottom of the pan, and then the whole batch carries that bitterness.
• •Serve small pieces. Kurumi-dofu is rich, and a restrained portion lets the nut sweetness stay elegant. Three small blocks on a plate often look more generous than one crowded slab.

Advance Preparation

• •The konbu and shiitake can soak overnight in the refrigerator for a rounder dashi.
• •The kurumi-dofu can be made one day ahead and kept covered in the refrigerator. Unmold and cut it close to serving so the edges stay clean.
• •The sauce can be made a day ahead. Keep it chilled, and spoon it onto the plate only at the end.

Frequently Asked Questions

Nutrition Information

1 serving (about 210g)