Add the cumin and coriander seeds to a pan on medium-heat. If you're using raw peanuts, roughly chop and add to the hot pan, as well. Continue to stir until the seeds and peanuts are fragrant and lightly toasted (about 3-4 minutes). Turn off the heat.
Add the toasted cumin, coriander, and peanuts to a small food processor and blitz for a few minutes until the majority of the seeds are broken down into a powder. (Alternatively, use a pestle and mortar.)
Chop and discard the stems of the chillies and the ends of the lemongrass stalk. (Get rid of the inside flesh and seeds of the chilli for a milder paste.) Discard the skins of the garlic cloves and onion. Add these to your food processor, roughly chopping, if needed, to fit into your food processor.
Measure out the remaining ingredients and add them to the food processor— turmeric, paprika, cinnamon, nutmeg, fresh ginger, zest and juice of one lime, sugar, and salt. Blitz until a paste forms. You may need to scrape down the sides of the food processor a few times. This usually takes about 5 minutes, but it can depend on the food processor you are using.
Store the paste in a sealed container in the fridge for 2 weeks. I use 2 tbsp per serving. Or, freeze 2 tbsp portions in an ice tray in the freezer for upto 3 months.