Bring 4 cups of chicken broth to a boil
Add shiitake mushrooms, bamboo shoots, and tofu
Season with soy sauce, dark soy sauce, crushed red pepper, white pepper, and sugar
Mix cornstarch with water to create a slurry and add to the soup to thicken
Stir in white vinegar and sesame oil
Slowly pour beaten eggs into the simmering soup while stirring to create egg ribbons
Garnish with scallions and serve hot
