Cut the prawns into four equal pieces and sprinkle with sake and salt.
Cut the lily bulb pieces into cubes of 1.5 cm. Cut off the stalks of the shiitake mushrooms and cut into quarters. Tear off the leaves of the mitsuba and cut the stems into 1.5 cm long pieces. Remove both the thick outer and the thin inner skin of the ginkgo nuts and cut in half lengthways.
Place the lily bulb and ginkgo nuts in a steamer and steam for 4-5 minutes, then sprinkle with a light layer of salt.
Beat the egg well then mix with the cool dashi then strain. Season with the light soy sauce.
Place 2pieces of chicken, ginkgo nut, prawn, and mushroom and 3 pieces of lily root and some mitsuba into each serving bowl and pour on the egg mixture from (5).
Place the bowls from (6) inside a pre-heated steamer and put the lid on. Cook on a medium heat for 2-3 minutes. When the surface and sides are starting to become firm, reduce the heat to medium low.
After 7-8 minutes, pierce with a skewer, and if a clear juice rises up through the hole, it is done. If not, steam on a low heat for a further 3-5 minutes.