Add chicken stock, seaweed, bonito flakes, soy sauce, sake and mirin to a pot.
Bring the mixture to a boil and remove from heat.
Allow the mixture to cool down and strain using a fine sieve.
* Chef’s tip: Strain the mixture through a fine sieve to ensure smooth consistency of the Chawanmushi.
Add the eggs into the mixture and mix well.
Place chicken and mushroom into cups/bowls that are suitable for steaming.
Distribute egg custard mixture equally into the cups/bowls.
Steam in a combi-steam oven or over a steamer for about 8 minutes.
To see if cooked, insert a toothpick into the middle of cup/bowl. If the toothpick comes out clean, the Chawanmushi is cooked.