What spice is a key component of the "mala" flavor profile and is known for causing a characteristic numbing or tingling sensation on the tongue?

Sichuan pepper

Sichuan pepper is the husk of a citrus-related fruit that contains hydroxy-alpha-sanshool, which interacts with nerve receptors to create a vibrating sensation. This effect is often paired with chili heat to define the signature flavor of Sichuan cuisine.