Preparation

• Remove the stems from the chiles. 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, in a heavy-duty mortar and pestle, pound the lemongrass and galangal until ground to a coarse paste, 3 to 4 minutes. Drain the chiles, and finely dice them. Add to the mortar in batches, sprinkling the salt over them after adding each batch. Pound until the mixture is fine and the oils are fully released from the chiles, about 15 minutes.
• Add the garlic, shallot, cilantro stems, and zest, and pound until all of the ingredients are fully incorporated into a smooth paste, about 20 minutes. You’re looking for a buttery consistency with no chunks, almost 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.