Hot-and-Sour Soup

Thinly slice fresh shiitake mushroom caps, discarding tough stems. (Or soak dried shiitake mushrooms in warm water; cover until softened. Discard tough stems; thinly slice mushroom caps.)

Bring stock to a boil in a large pot over medium-high. Add pork and mushrooms; simmer until cooked through, 1 to 2 minutes. Stir in vinegar, scallions, bamboo shoots, soy sauce, chile-garlic sauce (if using), sesame oil, and white pepper until combined; gently stir in tofu.

Stir together cornstarch and 1/4 cup water in a bowl until smooth and no lumps remain. Stirring gently and constantly, slowly pour cornstarch mixture in a steady stream into pot; cook until thickened, about 1 minute. Remove from heat. Gently stir soup in 1 direction to create a whirlpool. Slowly pour beaten eggs into soup in a thin stream to form egg drops. Garnish with additional scallions (if using).