1. Preparation
Gather all ingredients and tools: mixing bowl, whisk, fine strainer, ramekins, and a steamer.
Prepare dashi: If using instant dashi, dissolve 1 teaspoon in 1 cup of hot water, or prepare dashi from scratch by simmering kombu and bonito flakes.
Chop the shiitake mushrooms and scallions finely.
Prepare the chicken by cutting it into small bite-sized pieces.
Crack the eggs into a mixing bowl and beat them gently without producing too many bubbles.
Add the prepared dashi, soy sauce, mirin, and salt to the beaten eggs, mixing until combined.
2. Cooking
Strain the egg mixture through a fine strainer into another bowl to ensure a smooth texture.
Lightly grease the ramekins with a small amount of oil to prevent sticking.
Distribute the chopped chicken, mushrooms, and scallions evenly into the ramekins.
Pour the strained egg mixture over the ingredients in the ramekins, filling them about 80% full.
Cover each ramekin with aluminum foil to prevent water from dripping into the custard.
Set up the steamer over medium heat. If using a pot with a lid, bring water to a simmer.
Place the ramekins in the steamer and steam for 15-20 minutes, checking occasionally to avoid overcooking.
To test for doneness, insert a toothpick; it should come out clean when the chawanmushi is ready.
Once cooked, remove from the steamer carefully and let them cool slightly before serving.