Lime leaves are obtained from the kaffir lime, which is not a true lime at all but rather a subspecies of the citrus family. Used widely in south-east Asian cooking, especially Thai, lime leaves have a beautifully fragrant citrus smell and a fresh lemony flavour.
The Kaffir Lime has a dark green, warty skin which inspires an alternative name, leprous lime. There is virtually no juice inside, but the lime is valued for its zest and also for the marvellous perfume of its double leaf, no other lime, lemon or citrus can match it.
Grated Kaffir lime rind is added to some dishes, while the distinctive leaves are also used as a herb, particularly in Thailand. A spicy tom yum soup would be unthinkable without those leaves.
Kaffir lime leaves are very finely shredded and added raw to some salads, or added to cooked food.