Although the chewy lily buds and tree ear mushrooms add layers of texture to this soup, they can be omitted. Slideshow: Warming Soup Recipes
In separate bowls, cover the lily buds and mushrooms with hot water. Let soak until softened, about 30 minutes. Drain and thoroughly rinse the lily buds and mushrooms. Trim the tough ends from the buds and halve them crosswise. If using shiitakes, coarsely chop them.
In a large nonreactive saucepan, combine the chicken stock, lily buds, mushrooms, bamboo shoots, ginger and salt. Cover and bring to a boil over moderately high heat. Reduce the heat and simmer for 10 minutes. Stir in the vinegar and 1 1/2 teaspoons red pepper and boil over moderately high heat for 2 minutes.
Beat the cornstarch mixture into the soup in a steady stream. In a bowl, combine the egg and egg white and beat into the soup. Stir in the soy sauce, tofu and sesame oil and cook over moderate heat until warmed through. Season with red pepper and garnish with the scallions.
Dried lily buds, dried tree ear mushrooms and black soy sauce are available at Asian markets.
One Serving Calories 208 kcal, Protein 23 gm, Carbohydrate 13 gm, Cholesterol 53 mg, Total Fat 5.1 gm, Saturated Fat 1.3 gm.