Lightly toast the coriander seeds, cumin seeds, and white peppercorns in a dry pan until fragrant. Cool completely, then grind into a fine powder.

Slice the lemongrass, galangal, and chilies as finely as possible.

Add salt to the mortar first, followed by the chilies, and pound until broken down. Add the ground spices, then the aromatics gradually, pounding after each addition. Finish with the shrimp paste and continue pounding until a smooth, cohesive paste forms.

The finished paste should be thick, slightly coarse, and intensely fragrant. Do not add water or oil.