Lightly toast the coriander and cumin seeds in a dry frying pan, until fragrant.
Place the seeds into a pestle and mortar, and add the shallot, chillies, garlic, ginger, lemongrass and salt. Pound to a paste with the pestle. Alternatively, you can use a food processor to do this.
Cut the coriander stalks into chunks, and set aside the leaves to add to the finished curry. Add the coriander stalks and crumble the dried kaffir lime leaves to the mix, and continue to grind until fairly smooth.
Add the fish sauce and a pinch of white pepper. The curry paste is now ready to use. If not using immediately, the paste can be stored in a jar topped with a little oil and will keep in the fridge for a couple of weeks.