Step 1 Toast the coriander and cumin seeds: In a small saute pan, toast the seeds over medium heat until aromatic, 2 to 3 minutes. Shake the pan frequently to keep the seeds from burning on any sides. Remove from heat and grind the seeds, along with the cardamom seeds, in a spice grinder, coffee mill or using a mortar and pestle.
Step 2 Transfer the ground seeds to a mortar and pestle or a food processor. Add the nutmeg, clove, chiles, garlic, shallot, lemongrass, galangal and kaffir lime leaves. Pound the ingredients until finely pulverized with no visible chile pieces. Add the shrimp paste and mash to combine. (If using a food processor, drizzle in a little water as needed to puree the ingredients to a paste.) This makes about 1 1/4 cups curry paste, more than is needed for the recipe. The paste can be made up to 2 weeks in advance, covered and refrigerated until needed.