In a medium soup pot over high heat, bring your chicken stock to a boil, then add the sesame oil, vinegar, slices of white scallion ends, slices of shiitake mushrooms, salt, white pepper, sugar, optional turmeric, then turn the heat to low to take the soup to a simmer. Taste, and adjust the seasoning to suit your palate.

In a measuring jug, make the corn starch slurry by adding 2 tablespoons of corn starch to half a cup of boiling water, stirring well to completely combine, ensuring any lumps are dissolved. For a denser soup add an additional tablespoon of corn starch, but I don’t recommend more than 3 tablespoons.

Give the corn starch slurry a final stir before slowly pouring it into the simmering soup, stirring the soup as you do. Simmer for five minutes, stirring occasionally, then leave to sit for a minute and check the consistency of the soup. If it’s too thick, add some boiling water. If it’s not dense enough, make another slurry with ¼ cup of boiling water and 1 tablespoon of corn starch; no more than that as it will be too thick and your eggs won’t set properly.

To add the egg to the soup, use a large spoon or ladle to slowly stir the soup clockwise, and at the same time dip a large fork or pair of chop sticks into the whisked eggs then drizzle the egg into the soup to create wispy trails of egg; for small strands, use a teaspoon to very slowly drizzle the egg in; or for larger ribbon-like swirls or even round egg drops, slowly pour the egg from a small jug with spout into the soup. Take care not to pour or stir too fast otherwise the egg will emulsify.

Taste again and adjust the seasoning if needed, then distribute the soup between bowls, drizzle with sesame oil, sprinkle with white pepper and scatter some more green scallion slices on top.