Mapo Tofu Sauce

Place Sichuan peppercorns in a cold, dry wok or skillet. Heat over medium-low, shaking and stirring constantly. Toast until the peppercorns are fragrant — about 2–3 minutes. They should smell citrusy, floral, and slightly camphoraceous. Be careful: over-toasted Sichuan pepper turns bitter and loses the numbing hydroxy-alpha-sanshool compound that defines ma la. Immediately remove from the heat and grind coarsely in a mortar. The ground pepper should look like coarse black pepper.

Heat oil in a wok over medium heat. Add doubanjiang and stir-fry for 2–3 minutes until the oil turns deep red and the paste separates slightly. This step — frying the bean paste in oil — is called chao hong you ('frying red oil') and it is the flavor foundation of mapo tofu. Add minced garlic, ginger, and fermented black beans. Stir-fry for another 90 seconds until everything is aromatic and the raw garlic smell has mellowed. The paste will smell deeply savory, fermented, and slightly sharp.

Increase heat to high and add ground pork. Stir-fry briskly, breaking up any clumps, until the pork is fully cooked through and no pink remains — about 3 minutes. The pork should be in small, separate granules coated in the red chili paste, not large clumps. Each grain of pork should be individually seasoned by the doubanjiang. Once cooked, add the white parts of the scallions and stir for 30 seconds.

Add stock and soy sauce. Bring to a boil, stirring to incorporate all the stuck-on paste from the wok bottom. Reduce heat to a steady simmer and cook for 5 minutes to allow the flavors to meld. The sauce will be a rich, deep red. Taste and adjust salt with soy sauce. This is the moment to add silken tofu if serving as mapo tofu: add 400g silken tofu cut into 2.5 cm cubes, pushing them gently into the sauce with a spoon (never stirring or they will break). Simmer 3–4 minutes to heat the tofu through.

Give the cornstarch slurry a final stir (starch settles quickly). Pour in a slow, steady stream around the edges of the sauce, stirring gently. The sauce will thicken almost immediately. For tofu: use the back of a spoon to gently push the tofu, never stir. The sauce should be thick enough to coat tofu cubes and not pool excessively on the plate. Ladle into bowls. Finish with a generous shower of ground Sichuan peppercorns and the sliced green scallion tops. The pepper should be added last — heat destroys its numbing compounds.