Remove and discard the chilli stalks. Cut the chillies in half and remove and discard the seeds
Place the chillies into a bowl. Cover with hot water and set aside to soak for 15 minutes. Drain and roughly chop.
Dry-fry the shrimp paste for 2-3 minutes, turning once or twice. Set aside.
Dry fry the cloves, coriander, cumin, cardamon, and peppercorns over low heat, stirring frequently, for 3-4 minutes, or until aromatic. Transfer to a mortar and pestle.
Carefully crush the spices with the pestle and then add the shallots, garlic, galangal, lemongrass, coriander roots, chillies and salt, and pound to a smooth mixture, adding a little vegetable oil if needed.
Notes
The paste can be refrigerated for two weeks, or frozen for two months.