Laksa leaves, also known as Vietnamese coriander, is a herb used to garnish a bowl of laksa. It has a lemony, somewhat spicy and tangy flavor profile, and is available at Asian grocers and sometimes Thai specialty ingredient shops. It’s typically used to make spicy and sour dishes, and is a must for another style of laksa called asam laksa. Laksa leaves can be difficult to find outside of Asia, and the best substitute would be to use a combination of coriander (cilantro) and mint leaves.