How to Make Chinese Hot and Sour Soup 酸辣湯

• 7 ounces extra-firm tofu, drained
• 4 tablespoons soy sauce
• 1 teaspoon toasted sesame oil
• 3 tablespoons cornstarch, plus an additional 1 1/2 teaspoons
• 1 boneless, center-cut, pork loin chop (1/2 inch thick, about 6 ounces), trimmed of fat and cut into 1 inch by 1/8-inch matchsticks
• 3 tablespoons cold water, plus 1 additional teaspoon
• 1 large egg
• 6 cups low-sodium chicken broth
• 1 cup bamboo shoots (from one 5-ounce can), sliced lengthwise into 1/8-inch-thick strips
• 4 ounces fresh shiitake mushrooms, stems removed, caps sliced 1/4 inch thick (about 1 cup)
• 5 tablespoons Chinese black vinegar or 1 tablespoon red wine vinegar plus 1 tablespoon balsamic vinegar (see note below)
• 2 teaspoons chili oil (see note below)
• 1 teaspoon ground white pepper
• 3 medium scallions, sliced thin

BEFORE YOU BEGIN

To make slicing the pork chop easier, freeze it for 15 minutes. We prefer the distinctive flavor of Chinese black vinegar; look for it in supermarkets that carry a selection of Chinese ingredients. If you can't find it, a combination of red wine vinegar and balsamic vinegar approximates its flavor. This soup is spicy; for a less spicy soup, omit the chili oil altogether or add only 1 teaspoon.

INSTRUCTIONS

1. Place tofu in pie plate and set heavy plate on top. Weight with 2 heavy cans; let stand at least 15 minutes (tofu should release about 1/2 cup liquid). Whisk 1 tablespoon soy sauce, sesame oil, and 1 teaspoon cornstarch in medium bowl; toss pork with marinade and set aside for at least 10 minutes (but no more than 30 minutes).
2. Combine 3 tablespoons cornstarch with 3 tablespoons water in small bowl and mix thoroughly; set aside, leaving spoon in bowl. Mix remaining 1/2 teaspoon cornstarch with remaining 1 teaspoon water in small bowl; add egg and beat with fork until combined. Set aside.
3. Bring broth to boil in large saucepan set over medium-high heat. Reduce heat to medium-low; add bamboo shoots and mushrooms and simmer until mushrooms are just tender, about 5 minutes. While broth simmers, dice tofu into 1/2-inch cubes. Add tofu and pork, including marinade, to soup, stirring to separate any pieces of pork that stick together. Continue to simmer until pork is no longer pink, about 2 minutes.
4. Stir cornstarch mixture to recombine. Add to soup and increase heat to medium-high; cook, stirring occasionally, until soup thickens and turns translucent, about 1 minute. Stir in vinegar, chili oil, pepper, and remaining 3 tablespoons soy sauce; turn off heat.
5. Without stirring soup, use soupspoon to slowly drizzle very thin streams of egg mixture into pot in circular motion. Let soup sit 1 minute, then return saucepan to medium-high heat. Bring soup to gentle boil, then immediately remove from heat. Gently stir soup once to evenly distribute egg; ladle into bowls and top with scallions.