Kaffir lime leaves are also known as makrut lime and Thai lime, they are a crucial ingredient in Southeast Asian dishes. They have a wonderful citrusy aroma and are deep green and glossy. One leaf looks like two leaves joined together just like twins. Look for shiny, glossy leaves and avoid curled-up and dried-looking leaves. They keep well in paper or plastic in your fridge for a week and can also be frozen for up to a year.