Step 1

Wash the eggplants, then pull the flaps off the stem end. Use a fork to stab the eggplants in about 8 places for ventilation. (Residual moisture on the eggplant is great for microwaving.) Put the eggplants on a microwavable plate and microwave on high power for 4 to 6 minutes, until soft in most places and parts of the skin have turned brown. If you like, finish the eggplants over and open flame for a light smokiness. (See Note for open flame cooking.)

Step 2

Set the eggplants aside. When cool enough to handle, remove the charred patches of skin if you charred it. It’s ok to leave stubborn bits on the eggplant. (If you only microwaved it, then keep the skin intact.) Cut each eggplant into slender pieces about the length and width of your pinkie finger. Arrange in a shallow dish.

Step 3

Dissolve the dashi in the warm water then season with about 1tablespoon of soy sauce for a salty, savory finish. Taste, and if sweetness is needed, add about 1 1/2 teaspoons of mirin. Pour the dashi over the eggplants. The eggplant should be nearly covered. Let sit at moderate room temperature, uncovered, for up to 4 hours, spooning dashi over the eggplant once or twice. The eggplant will absorb some of the dashi.

Step 4

To serve, carefully pour off most of the dashi into a small bowl, avoiding the eggplant falling out. Sprinkle the green onions on top of the eggplant, mound it in the center, or do both. Sprinkle togarashi over the eggplant. Serve the eggplant with the reserved dashi on the side for people who want more sauce.