In separate bowls, cover the lily buds and mushrooms wiht hot water. Let soak until softened, about 30 mnutes. 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 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 scallions. Per serving: 319 Calories; 10g Fat (27% calories from fat); 15g Protein; 45g Carbohydrate; 48mg Cholesterol; 2233mg Sodium Recipe by: Food and Wine, April 1996