Bai Prig ใบพริก
Chili Leaves don’t play an important role like galangal or kaffir lime leaves in most Thai dishes but when it comes to green curry paste, they shine. They give green curry paste its beautiful bright green color without adding so many green chilies, the curry would be too hot to eat. The leaves themselves have no heat and little flavor; they can best be thought of as natural food coloring. They are also used in many other dishes, soups and curries.
It's convenient to have a chili plant, but if not, Asian farmers at farmers markets have just about the whole plant (chili with leaves attached on the branches) available mid to late summer. I pick off the leaves for my green curry paste then wash and freeze the rest of the chilies.