Toast the coriander seeds, cumin seeds, and white peppercorns in a dry pan until fragrant. Grind them in a mortar or spice grinder.

In a blender, add the softened red chilies, shrimp paste, lemongrass, garlic, shallots, galangal, lime zest, salt, and the toasted spices. Blend until smooth. Add a little water if needed.

Heat the oil in a pan over medium heat, then add the curry paste and cook, stirring constantly, for about 5 minutes, until fragrant and the oil begins to separate from the paste.

Let it cool and transfer to an airtight jar. The paste will keep in the refrigerator for up to two weeks, or you can freeze it in small portions for future use.