40 dried lily buds (about 1/2 ounce)
1/4 cup small dried tree ear mushrooms or dried shiitake mushroom caps
5 cups chicken stock, unsalted or low-sodium
1/2 cup drained canned bamboo shoots, rinsed and julienned
2 teaspoons minced peeled fresh ginger
1/2 teaspoon kosher salt
3 tablespoons red wine vinegar
1 teaspoon crushed red pepper
3 tablespoons cornstarch
3 tablespoons water
1 large egg
1 large egg white
4 ounces firm tofu, drained and cut into 1/3-inch cubes
2-1/2 tablespoons soy sauce
1 teaspoon toasted sesame oil
Place lily buds and mushrooms in a small bowl, and add very hot water to cover by 1 inch. Let soak until softened, about 30 minutes. Drain and rinse thoroughly. Trim and discard tough ends from buds, and cut in half crosswise. Coarsely chop mushrooms.
Stir together lily buds, mushrooms, chicken stock, bamboo shoots, ginger, and salt in a large nonreactive saucepan over high. Cover and bring to a boil. Reduce heat to medium, and simmer 10 minutes. Stir in vinegar and red pepper; increase heat to medium-high, and boil mixture 2 minutes.
Whisk together cornstarch and 3 tablespoons water in a small bowl. Whisk cornstarch mixture into chicken stock mixture in a slow, steady stream; cook 1 minute. Beat together egg and egg white in a medium bowl. Pour egg mixture into chicken stock mixture in a slow, steady stream, stirring gently. Stir in tofu, soy sauce, and sesame oil, and cook, stirring occasionally, until warmed, about 2 minutes.