Dry roast the coriander seeds in a small pan until fragrant. In a pestle and mortar or small spice grinder, grind the coriander together with the peppercorns.
Drain the red chili and in a small processor or using a pestle and mortar combine the chilis with the lemongrass, garlic, coriander root, galangal, shallot, lime peel, salt and shrimp paste. Pound or blend all ingredients, adding a little water if required until the ingredients are well combined and have formed a smooth paste.
Note: If you are buying a red curry paste always check the ingredients and buy one which has no preservatives or other unfamiliar ingredients.