Chawanmushi (Savory Japanese Custard)

Whisk the egg in a bowl until it forms a completely smooth mixture.

Add the dashi, soy sauce, mirin, and salt to the egg mixture. Gently mix until all seasonings are incorporated.

Distribute the chicken, sliced kabocha squash, and sliced shiitake mushrooms into individual ramekins that will be steamed.

Strain the liquid egg mixture through a fine-mesh sieve over the ramekins, ensuring there are no bubbles or impurities (remove bubbles with a spoon, if necessary).

Cover each ramekin with plastic wrap.

Place the ramekins in the steamer, starting with high heat for 3 minutes.

After 3 minutes, reduce the heat to medium-low and cook for another 10 minutes while keeping the pot lid slightly ajar (using chopsticks, for example).

Turn off the heat and serve the Chawanmushi.