Fill a steamer large enough to hold four 6- to 7-ounce chawanmushi cups (see Cook’s Note) with about 2 inches of water and bring to a simmer over medium heat while you assemble the chawanmushi.

For the filling: Divide the chicken, shrimp, gingko nuts, shiitakes and mitsuba among the chawanmushi cups, layering them on top of each other in order; slip 1 slice of fish cake into each cup along the side.

For the custard. Add the eggs to a medium bowl and gently whisk using chopsticks or a fork, aerating them as little as possible. Add the Dashi, light soy sauce, mirin and ½ teaspoon salt and mix just until combined. Strain the mixture through a fine-mesh strainer into a large measuring cup or another medium bowl. Pour or ladle equal amounts of the custard into each cup, popping any large bubbles, then place the lids on the cups or tightly cover each cup with foil.

When the water is boiling, reduce the heat to low and carefully place the covered cups into the steamer. Cover the steamer and steam until the custard is just set, 15 to 20 minutes. (To test, using a chopstick or skewer, poke a hole into the center of one of the chawanmushi; if clear liquid fills the hole, it’s ready.) Carefully remove the cups from the steamer (if using lids, it’s easier to remove the lids first, then the cups). Serve, covered, hot, warm or cold and with small spoons.

Combine the kombu and 3 cups cold water in a medium saucepan and let sit for about 30 minutes. (You can skip this step if you’re short on time, but it does lend a little extra flavor.) Heat over medium heat until the water comes to a near boil but doesn’t actually boil, about 5 minutes. Discard the kombu.

Add the katsuobushi evenly over the water, bring to a boil over high heat, then immediately remove from the heat. Let steep for about 10 minutes without stirring.

Pour the dashi through a fine-mesh strainer into a bowl or quart-size measuring cup. Do not press down on the katsuobushi, which can make the dashi cloudy and/or bitter. Dashi is best used the day it is made, but can be cooled and refrigerated in an airtight container for up to 3 days. Yield: about 2 ½ cups