What is Sichuan pepper?

Sichuan pepper isn't actually pepper, but the dried red-brown berries of a type of ash tree. The berries are dried and then sold whole or crushed to a powder.

Try to buy the freshest berries you can find, because they quickly lose their lemony, peppery pungency. Sichuan pepper has a characteristic mouth-numbing quality that's typical of many Sichuan dishes. Sichuan pepper is also one of the spices in Chinese five-spice powder.