Hot and Sour Soup (酸辣汤)

Yield:

• 4 servings

Time:

• 30 minutes

Difficulty:

• Moderate

Ingredients

• 1/3 cup dried shiitake mushrooms
• 1/4 cup dried woodear mushrooms
• 1/4 cup dried lily flowers
   
• 1/2 lbs (230 g) pork loin or chicken breast, cut into thin strips [optional]
• 1/2 tablespoon Shaoxing wine or dry sherry
• 1/4 teaspoon salt
• 1/2 tablespoon cornstarch
   
• 2 teaspoons minced ginger
• 2 green onions chopped, or more to taste
• 2 tablespoons Chinkiang vinegar, or more to taste
• 1 teaspoon white pepper powder (or 1/2 teaspoon for a less spicy dish)
• 6 cups water, vegetable stock, or chicken stock
• 1/2 block (8 oz / 227 g) firm tofu, cubed
• 1 tablespoon light soy sauce
• 3 tablespoons cornstarch
• 1 teaspoon salt or to taste
• 2 eggs, beaten
• 1 teaspoon sesame oil

Instructions

1. Gently rinse dried shiitake mushrooms, dried wood ear mushrooms, and lily flowers with tap water. Soak each of them with 1.5 to 2 cups warm water in three big bowls. Rehydrate for 30 minutes to 1 hour, until tender. 
2. Slice shiitake mushrooms into strips. Snip off the tough ends of lily flowers and discard. Remove tough ends of wood ear mushrooms, then chop into bite-sized pieces.
3. Combine pork or chicken (if using), Shaoxing wine, salt and cornstarch in a bowl. Mix well by hand. Marinate for 10 - 15 minutes.
4. Add Chinkiang vinegar and white pepper into a small bowl. Mix well until the white pepper is completely dissolved.
5. Add water or stock, ginger, and green onion into a pot and heat over medium-high heat. 
6. Add rehydrated mushrooms and lily flowers, with their soaking water, to the pot. Add tofu and bring to a simmer. 
7. Add soy sauce and turn to medium-low heat.
8. Mix the cornstarch with 1/4 cup of water in a bowl until cornstarch is fully dissolved. Slowly swirl the cornstarch slurry into the soup. Stir to thicken the soup.
9. Add the pork from step one into the soup, stirring several times to prevent the pork strips from sticking together. Add the salt. 
10. Slowly swirl in the beaten egg and stir well to create threads. .
11. Remove the pot from stove. Add the vinegar and pepper mixture and stir to mix well.
12. Garnish with cilantro and drizzle with sesame oil. Give it a final stir.
13. Serve hot.

Notes:

• To my taste, needs more vinegar.  Spiced chili oil is also a nice garnish.  
• Chinkiang vinegar is essential.  Do not try to substitute another vinegar.  Similarly, use white pepper, not Szechuan pepper.
• Add vinegar and pepper only after removing from heat – else the vinegar flavor diminishes and the pepper can become bitter..

Variations:

• Skip the meat if you want to create a vegetarian dish.
• Use chicken stock or vegetable stock instead of water if you are not using the dry ingredients (shiitake mushrooms, lily flowers, and wood ear mushrooms) in this recipe.
• Other nice additions include julienned bamboo shoots, napa cabbage cut into ribbons, and bok choy. 

Source: Omnivore's Cookbook.