If using dried wood ear mushrooms, soak according to package instructions until soft, then drain and slice into thin strips. Clean and thinly slice shiitake mushrooms, julienne carrot, drain and julienne bamboo shoots. Thinly slice chicken across the grain and cut tofu into 1/2-inch strips. Peel and halve shrimp if large.

Separate scallion whites from greens and mince garlic and ginger. Beat the egg in a small bowl and set aside.

Make Stock

In a large pot over medium-high heat, add 6 cups chicken or vegetable stock and 1 cup water. Bring to a gentle simmer.

Add 3 tablespoons light soy sauce, 3 tablespoons black vinegar (or rice vinegar), 1 teaspoon white pepper, 1 teaspoon sugar, 1 tablespoon chili paste (or 1 tsp chili flakes), 1 teaspoon sesame oil, and 1/2 teaspoon salt. Stir to combine and taste; adjust soy sauce or vinegar for balance of saltiness and sourness.

Cook Proteins & Vegetables

Add the minced garlic, minced ginger, and scallion whites to the simmering broth. Let simmer 1 minute to release aromatics.

Add sliced shiitake, wood ear mushrooms, bamboo shoots, and julienned carrot to the pot. Simmer 2–3 minutes until vegetables begin to soften.

Stir in sliced chicken and shrimp. Cook 2–3 minutes until shrimp are pink and chicken is cooked through. Add tofu gently so it warms without breaking apart.

Thicken & Finish

While the soup simmers, make a cornstarch slurry: whisk 3 tablespoons cornstarch into 1/2 cup cold water until smooth.

Slowly drizzle the slurry into the pot while stirring gently. Bring soup to a simmer; it will thicken in 1–2 minutes. If you prefer thicker soup, make an additional 1–2 tablespoons slurry.

Once the soup has slightly thickened, reduce heat to low. Slowly drizzle the beaten egg in a thin stream into the simmering soup while stirring gently in one direction to create silky egg ribbons. Turn off heat after the egg sets (about 30 seconds).

Taste and adjust seasoning with additional vinegar for sourness, chili for heat, or salt/soy for saltiness.

Stir in thinly sliced scallion greens and 1 teaspoon sesame oil. Remove from heat.

Serve

Ladle hot and sour soup into bowls. Garnish with chopped cilantro (if using) and extra white pepper or chili to taste. Serve immediately.