The main ingredient is
phrik num, long slender green chiles that are almost exclusively used in this particular dish.
Northern Thais, fond of their vegetables, take the slender dark green chiles known as
phrik num, roast them along with garlic and shallots, and mash the results together in the dish known as nam
phrik num.
Using a mortar and pestle, grind the grilled ingredients together with the salt until blended but still chunky (
phrik num should ideally be in long strands or strips).