Preparation

• Remove the stems from the chiles, and shake out and discard the seeds. Break the chiles into pieces, and soak them in hot water for 20 to 30 minutes to soften.
• Meanwhile, combine the coriander and cumin seeds in a medium skillet, and toast, stirring constantly, over medium heat until the seeds are aromatic and slightly darkened, 2 to 3 minutes. Let cool.
• Using a heavy-duty mortar and pestle, grind the toasted seeds into a fine powder. Remove and set aside.
• Combine the lemongrass, turmeric, and galangal in the mortar, and pound until ground to a coarse paste, 3 to 4 minutes.
• Drain the chiles, and finely dice them. Add to the mortar, and sprinkle with the salt. Pound until the mixture is fine and the oils are fully released, about 10 minutes.
• Add the garlic, shallot, cilantro stems, zest, and reserved spices, and pound until the ingredients are incorporated into a smooth paste, about 20 minutes. You’re looking for a buttery consistency with no chunks, like tomato paste. Add the shrimp paste. It will almost melt into the curry paste as you spread it around.
• Use the curry paste immediately, or store it in an airtight container covered with a thin layer of oil for up to 1 month in the refrigerator or 3 months in the freezer.