Kaffir lime leaves are an aromatic Asian leaf most often used in Thai, Indonesian and Cambodian recipes. They have a spiced-citrus flavour which is a lot lighter and zestier than a bay leaf or curry leaf. Perfect for lifting a coconut-based broth or fragrant fish curry.
 
When cooking with kaffir leaves, it's best to think of them as a kind of aromatic bay leaf — most commonly used to infuse curries, soups, stir fries or stocks.