Gently warm the dashi until just lukewarm; it should not be hot enough to start cooking the eggs.
430 ml dashi stock
Set up a steamer over a gentle simmer, large and stable enough to hold the custard dishes. Keep the water at a low bubble to avoid bubbles or cracks in the custard.
Whisk the lukewarm stock with the eggs until completely combined.
3 eggs
Stir in the soy sauce and mirin.
0.5 tablespoon mirin, 1 teaspoon light soy sauce
Strain the mixture through a fine sieve twice to remove any egg strands and ensure an ultra-smooth custard.
Pour the custard into heat-proof serving dishes, leaving a little space at the top.
Divide the shrimp and shiitake evenly among the dishes.
50 g small shrimp, 2 shiitake mushrooms
Cover each dish loosely with aluminum foil to protect the surface from dripping condensation.
Place the dishes in the steamer and cook for about 8 minutes. Timing will vary with vessel size and steamer temperature; the custard is ready when the surface is set and jiggles gently.
Garnish with mitsuba and serve immediately.
mitsuba leaves
Notes
Use any clear, flavorful broth you have on hand. Traditional dashi is ideal, but chicken stock works beautifully, and even tomato water (strained tomato purée) is delicious thanks to its umami punch.Cover each dish with a piece of foil to prevent condensation from the steamer lid from dripping onto the custard and marring its smooth surface.