15g dried wood ear mushrooms (about 3)

2 cups warm water, plus 4 cups cool water

250g boneless pork loin, cut into thin strips

1 1/2 tsp Shaoxing wine (Chinese rice wine; may substitute dry sherry)

3 tbsp cornstarch combined with ¼ cup water, plus 1 1/2 teaspoons cornstarch

1 ¼ tsp salt

5 tbsp Chinkiang black vinegar (see headnote), or more as needed

2 tsp chili oil, plus more for optional garnish

1 tsp ground white pepper

10 thin slices fresh ginger

2 tbsp regular or low-sodium soy sauce

¼ cup canned bamboo shoots, drained and cut into matchsticks

250g firm tofu, cut into 1cm cubes

2 large eggs, lightly beaten

2 to 3 spring onions, thinly sliced

Steps

1 Gently rinse the dried shiitake and dried wood ear mushrooms with tap water. In a medium bowl, soak the mushrooms in the 2 cups warm water until softened, about 20 minutes. Squeeze the excess water out of the mushrooms and reserve the water. (Strain the mushroom water through a fine-mesh strainer if it looks too gritty.)

2 Discard the stems from the shiitake mushrooms and slice the caps into strips. Discard the tough ends of the wood ear mushrooms before chopping into bite-size pieces.

3 In a medium bowl, combine the pork, Shaoxing wine, 1 ½ tsp cornstarch and ¼ tsp salt. Mix until the pork is evenly coated, and let it marinate on the counter for 10 to 15 minutes.

4 In a small bowl, stir together the black vinegar, chili oil and pepper.

5 In a medium saucepan over medium-high heat, combine the mushroom water, 4 cups cool water and sliced ginger and bring to a boil. Cook for 2 to 3 minutes, then, using a slotted spoon, remove and discard the ginger.

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6 Add the soy sauce, followed by the rehydrated mushrooms and bamboo shoots, and simmer for 5 minutes. Give the cornstarch mixture a quick stir to recombine and gradually stir into the soup. The soup will become slightly thickened.

7 Add the pork, including the marinade, to the soup, stirring to separate any pieces that stick together. Continue to simmer until the pork is no longer pink, about 2 minutes. Carefully add the tofu, so the broth does not splash. Stir in the remaining 1 teaspoon salt.

8 Slowly pour the eggs into the soup in a steady stream while stirring continuously with a long spoon or chopstick. The eggs should cook immediately and look like long yellowish-white strands. Turn off the heat once you see the strands, so the eggs do not overcook, and stir in the black vinegar mixture.

9 Serve hot, garnished with scallions and additional chili oil, if desired.

Notes:

• Make it veggie by replacing the pork with more tofu.
• If you like your soup particularly hot or sour, add more chili oil or vinegar to taste.
• The soup will keep in the fridge for up to three days.