Hot Sour Soup Recipe

Prepare mushrooms

Place the dried shiitake mushrooms in a bowl and cover with 1 cup hot water. Let soak 20–30 minutes until soft. Reserve the soaking liquid by straining through a fine-mesh strainer or coffee filter to remove grit; set both mushrooms and liquid aside.

In a 4–5 quart pot, combine the chicken or vegetable stock and 1 cup reserved mushroom soaking water (or plain water if none). Bring to a gentle simmer over medium-high heat.

Add light soy sauce, black vinegar, sesame oil, white pepper, sugar, and 1/2 tsp salt to the simmering stock. Taste and adjust soy or vinegar so the broth has a clear balance of salty and noticeably sour (hot-sour is tangy). Keep at a gentle simmer.

While the stock comes to a simmer, heat 1 tablespoon neutral oil in a small skillet over medium heat. Add julienned ginger and minced garlic and stir for 30–45 seconds until fragrant but not browned. Add the sliced white parts of the scallions and cook 30 seconds more. Pour the aromatics into the simmering broth.

Slice the rehydrated shiitake caps into thin strips; if using wood ear mushrooms, slice into thin strips as well. Add all mushrooms to the simmering broth.

If using chicken: add the thinly sliced chicken to the simmering broth and cook 2–3 minutes until just opaque and cooked through. If not using chicken, skip this step.

Add the tofu matchsticks to the pot and simmer gently 2 minutes so they heat through and absorb some flavor.

Make a cornstarch slurry by whisking 3 tsp cornstarch with 3 tablespoons cold water until smooth. With the soup at a gentle simmer, slowly stream the slurry into the pot while stirring the soup in one direction to avoid lumps. Continue simmering for 1–2 minutes until the broth slightly thickens to a silky consistency (it should coat the back of a spoon lightly).

Remove the pot from the heat momentarily. Slowly drizzle the lightly beaten egg into the simmering (but not violently boiling) soup in a thin stream while stirring gently in one direction to form delicate egg ribbons.

Return the pot to low heat for 20–30 seconds to set the egg, then turn off the heat. Stir in 1 teaspoon chili paste (or to taste) and 1 tablespoon extra white vinegar. Taste and adjust seasoning: add more vinegar for sourness, soy for salt, or white pepper for heat. If needed, add up to 1/2 tsp more salt.

Finish with 1/2 tsp toasted sesame oil and the thinly sliced scallion greens. Ladle soup into bowls and serve immediately, offering extra vinegar, chili paste, and white pepper at the table.