Makrut lime leaves (also known as 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.

The leaves have an unusual, hourglass shape, which almost looks like two leaves joined together at the tip. Lime leaves are rich with natural oils, so it's always best to use them fresh if possible. This is tricky for anyone living outside South East Asia though. Luckily, various processing techniques enable makrut lime leaves to be transported round the world, where they are sold in specialist ingredient shops. It's possible to buy preserved, frozen or powdered lime leaves, though they are most widely available in dried, or freeze-dried form.

When cooking with makrut 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. Cooks 'bruise' or crush fresh leaves in their hands to help release their aromas before adding them to a dish. When using dried leaves, the heat and moisture of cooking helps them release their flavour. Aside from soups and broths, makrut lime leaves can also be used to infuse anything from a pickling juice to a salt cure or sugar syrup.

It's a little more unusual, but some recipes use fresh makrut lime leaves as an ingredient in their own right, either pounding them into a pulp, or slicing them finely — as Nuno Mendes demonstrates in his recipe Thai Explosion II.