This lovely dish, from Naoko Boerger, a Tokyo native who now lives in Palo Alto, California, is perfect for autumn. It uses three very different types of mushrooms, shiitake, shimeji, and oyster. The tiny shimeji mushrooms are sold in 100-gram clumps. If you can't find them, you can use another variety of wild or domestic mushroom. The tofu puff, which you can find in the refrigerator case of Asian markets, soaks up the mushroom flavor wonderfully, but if you can't find it in your area, leave it out. Naoko serves the rice with fried shrimp coated with bread crumbs, and a green bean salad with sesame dressing.
MACHINE: Medium (6-cup) rice cooker or InstanPot; fuzzy logic or on/off CYCLE: Regular YIELD: Serves 6
Wash the rice. Place the rice in a bowl (or use the bowl of your rice cooker) and fill the bowl about half-full with cold tap water. Swirl the rice in the water with your hand. Carefully pour off most of the water, holding one cupped hand under the stream to catch any grains of rice that are carried away with the water. Holding the bowl steady with one hand, use the other to rub and squeeze the wet rice, turning the bowl as you go, so that all the rice is "scrubbed." The small amount of water in the bowl will turn chalky white. Now, run cold water into the bowl, give the rice a quick swish, and carefully drain off the water as before. Repeat the scrubbing and pouring-off process two more times. By the third time, the water you pour off will be nearly clear.
Place the drained rice in the rice cooker bowl. Cover with a clean, wet tea towel and let the rice rest for 30 minutes.
Set a kettle of water on to boil. Meanwhile, rinse the fresh shiltake mushroom, if using. If using the dried mushrooms, place in a small bowl, cover with water, partially cover with plastic wrap, and microwave on high for 2 minutes, or cover with warm water and let soak for 30 minutes. Drain, pat dry, and thinly slice.
Break apart the shimeji mushrooms; trim and discard the ends. Wipe gently with a damp tea towel or paper towel to clean. Gently brush or wipe any dirt from the oyster mushrooms, then slice them, trimming and discarding the ends. Put all the mushrooms in a medium-size bowl. Sprinkle the soy sauce over them and set aside.
Place the tofu puff in a colander in the sink and pour boiling water over it to remove excess oil. Dry with a paper towel and cut into thin slices. Toss the tofu slices with the mushrooms and soy sauce.
Add the sake and dashi to the soaked rice. The dashi should not quite come up to the 4-cup level on the rice cooker bowl. (The mushrooms will contribute some moisture to the dish.) Add the mushroom mixture to the rice; stir to combine. Close the cover and set for the regular cycle.
When the machine switches to the Keep Warm cycle, let the rice steam for 15 minutes. Fluff with a wooden or plastic rice paddle or wooden spoon, mixing thoroughly but gently. This rice will hold on Keep Warm for 1 to 2 hours. Serve hot, with some soy sauce on the side, if desired.