Salsa Arriera (Mule drivers' salsa)
20 serrano chillies, stems removed
¼ small white onion, peeled
fresh garlic to taste, 1-3 cloves
Thoroughly blacken and blister the chillies in a dry frying pan, under a broiler, or over a fire. Put all ingredients into a blender and blend to a coarse paste, adding only enough water to make the mix fall into the blender blades.
This can be a very hot salsa. It may be tamed by adding cilantro and or tomatillos.
Add lemon grass, kaffir leaves, galanga, and nam pla, and you get gang khiew wan, Thai green curry paste.