- 2 baby leeks (1/2 lb total; white and pale green parts only), cut diagonally into 1/8-inch-thick slices
- 10 oz soft or firm tofu (not silken or extra-firm), drained and cut into 1/2-inch cubes
- 1 tablespoon peanut oil
- 1/4 lb ground beef
- 1 teaspoon Chinese rice wine (preferably Shaoxing) or medium-dry Sherry
- 1 teaspoon dark soy sauce
- 1/2 tablespoon Chinese chile bean sauce or paste
- 1 teaspoon minced peeled fresh ginger
- 1 teaspoon mild pure chile powder
- 1/2 teaspoon Chinese fermented black beans, soaked in water 10 minutes and drained
- 1/4 cup chicken broth
- 1/2 teaspoon potato starch or cornstarch mixed with 2 teaspoons cold water
- Accompaniment: white rice
- Garnish: 1/2 teaspoon Sichuan peppercorns, toasted and ground with a mortar and pestle
- Wash leeks in a bowl of cold water, then lift out and drain well.
- Dissolve 1/2 teaspoon salt in 2 cups hot water in a medium bowl, and add tofu. Soak 5 minutes, then drain in a sieve.
- Heat a wok or 12-inch heavy skillet over high heat until a bead of water dropped onto cooking surface evaporates immediately. Add oil, swirling wok to coat, and heat until it begins to smoke. Add beef and stir-fry, breaking up lumps, until no longer pink, about 2 minutes. Stir in wine and 1/2 teaspoon soy sauce and stir-fry 30 seconds.
- Add chile bean sauce and stir-fry until fragrant, about 15 seconds. Add ginger, chile powder, and black beans and stir-fry until fragrant, about 30 seconds. Add broth, remaining 1/2 teaspoon soy sauce, and tofu, then reduce heat and simmer, stirring gently, about 2 minutes.
- Add leeks and simmer, stirring occasionally, until just tender, 2 to 3 minutes. Stir potato starch mixture and add to tofu, then cook, stirring, until sauce is thickened, about 1 minute.