One of China’s most ubiquitous culinary exports, Sichuan cuisine is famous for the 麻辣, or málà (mouth-numbing spice), that comes in the form of a peppercorn (花椒, huā jiāo). Prompting a tingling sensation that has been likened to licking a nine-volt battery, the lemony husk is tossed into dishes with dried chili peppers, and never more skillfully than at Yu Xin.