Wash the oysters by changing the water 2–3 times, pat them dry, and coat with potato starch (not listed in ingredients).

Separate chrysanthemum greens into leaves and stems. Slice the stems diagonally and cut the leaves into bite-sized pieces.

Boil water in a pot, add salt (not listed in ingredients), and cook spaghetti for 1 minute less than the package instructions. Drain the water.

Heat half the butter in a frying pan, add oysters, and sauté over medium-low heat until plump. Remove from the pan.

Add the remaining butter and shimeji mushrooms to the pan. Sauté until softened, then add chrysanthemum stems and stir-fry together.

Add water, consomme powder, and bring to a boil. Dissolve white miso into the mixture, then add milk and simmer gently.