Kaffir lime (Citrus hystrix), also known as Mauritius papeda, originally comes from tropical Asia. It was introduced to the west by emigrants.
Kaffir lime leaves come from a very slow-growing shrub. This is why the price is at the higher end of the scale.
In a culinary setting, kaffir lime leaves are mainly used in Asian cuisine. They add a fresh, citrusy taste to any dish.
Kaffir lime leaves can either be cooked as part of the dish and removed prior to serving, or sliced, cooked with the rest of the ingredients and eaten.
At fridge temperature, kaffir lime leaves can be kept for several days.