Heat the chicken stock in a medium soup pot until small bubbles rise steadily, then stir in the sesame oil, salt, sugar, white pepper, MSG, and turmeric. Taste the hot broth and adjust the seasoning until it is savory, gently peppery, and evenly golden.

Stir the cornstarch mixture until smooth, then pour it into the simmering broth in a thin stream while stirring continuously. The broth should become lightly thickened and glossy without any starchy lumps.

Move a ladle through the soup in one slow circular motion and drizzle in the lightly beaten eggs in a narrow, steady stream. Let the ribbons turn pale yellow on the surface before disturbing them, then stop stirring once the egg has set.

Ladle the soup into bowls and scatter the chopped scallion over each serving. The finished soup should hold floating egg flowers in a warm, silky broth.