Kaffir lime leaves come from the Kaffir lime tree, a lime tree native to Indonesia. The leaves are highly aromatic and are widely used in Asian cuisines, especially Thai. They are easily recognisable by their emerald-green, double leaf lobes, which makes them appear as if two leaves are joined together.Kaffir lime leaves may be used fresh or dried, depending on the recipe or usage. 

Add them straight to wet dishes, rehydrate them by steeping in warm water for a few minutes before chopping.