Prepare the Ingredients: Thinly slice the shiitake mushrooms. Pick the crab meat into bite-sized pieces. Divide the crab and mushrooms equally into the bottom of two heat-proof teacups or ramekins.

Make the Custard Base: In a bowl, gently beat the eggs with chopsticks (do not whisk forcefully, to avoid creating bubbles). In another bowl, combine the cooled dashi stock, light soy sauce, mirin, and salt.

Combine and Strain: Gently mix the dashi broth into the beaten eggs. Pour the egg mixture through a fine-mesh strainer into a measuring cup. This crucial step guarantees a silky-smooth texture.

Fill the Cups: Slowly pour the strained egg mixture into the teacups over the crab and mushrooms. Cover each cup tightly with aluminum foil.

Steam: Place the cups in a steamer basket over boiling water. Steam on high heat for 3 minutes, then lower the heat to the lowest setting and steam for another 10 to 12 minutes until the custard is just set and jiggles slightly. Top with Mitsuba before serving hot.