Place the cumin and coriander seeds in a pan without adding any oil. Dry-fry them, stirring, over medium heat for 1 to 2 minutes until they are slightly browned, and give off a roasted aroma.
Coarsely chop the chilies and soak in water for 10 minutes. Drain. Pound all the ingredients together to produce a fine paste which goes well with beef and pork.
From "Discover Thai Cooking" by Chaslin, Canungmai and Tettoni, Times Editions, Singapore. 1987