Finely slice the white part of the spring onion on the diagonal and set aside. Then finely slice the green part of the spring onion in flat strips against the grain, julienne style. Set these aside. That is all the chopping needed.
Next, give the 3 eggs a good whisk in a bowl and set aside.
Bring 4 ½ cups of chicken broth to a boil. As the broth heats, stir in the turmeric, mirin, soy sauce, white pepper, and rice wine vinegar.
Add the whites of the spring onion as the broth nears a boil.
Turn the broth down to a rolling simmer and let the onion cook for 3-4 minutes.
In another bowl, stir 2 ladles of hot broth into the cornstarch and whisk it well into a slurry. Then stir the cornstarch slurry back into the boiling broth and cook for one minute.
With the broth on a rolling boil, stir in the beaten egg in a thin stream, a little at a time, and pull the egg through the soup with chopsticks. I added in the eggs over 3 pours. Wait for the soup to come back to a boil before adding in the next round of eggs.
Remove the soup from the heat and allow it to sit for a minute or two. Then stir in the toasted sesame oil and most of the green part of the spring onion.
Ladle up the egg drop soup in large broad soup bowls and finish with a sprinkling of the green parts of the spring onion. Enjoy!
