To PrepSoak the chillies in hot water for 5 mins to hydrate, before draining and cutting in to sections. Slice the shallots, coriander roots, galangal and lemongrass into small sections. Add the chillies in to the pestle and mortar and grind lightly to break the chillies up. When the sections have begun to break down, add the salt and continue to grind. Add in the lemongrass and grind till the sections have broken down. Repeat this process next with the galangal, garlic, kaffir lime zest, cilantro roots and lastly with the shallots. Continue to grind all of the ingredients together until the mixture turns into a fine paste.At this point, add in the shrimp paste and continue to grind until shrimp paste has been fully incorporated in to the paste.