Mapo tofu is one of the most well-known dishes from Sichuan in southwest China, made of tofu, minced pork, and spices.  A plate of well-cooked mapo tofu is aromatic, soft, and numbingly spicy. That fiery sensation, which is quite addictive to some, comes from peppercorn, a local spice from the region. Fermented bean paste, or doubanjiang, adds umami to the dish. The area is known for being humid, so people eat spicy food to get rid of the damp feeling in their bodies. It is said that the dish...