Kaffir leaves or kaffir lime leaves are easily identifiable by its double, figure 8 shaped leaves. Used for its delicate, fragrant, lemony flavor, it’s their perfume you smell in Thai green curry or Tom Yum Soup. The kaffir tree has round fruit that looks like lime.
Tear leaves to release its oil before cooking. Shown right in photo.
Kaffir leaves are available dried but if you find them fresh, buy a packet and freeze in a sealed plastic container. The frozen leaves retain their perfume and is so much better than dried. I was excited to find them in the Korean supermarkets near me. Don’t wash before freezing. Also available in Thai and Vietnamese stores.