Cut up the chillies a little for easier chopping, in 2-3 pieces, roughly, depending on the size.
Pick the leaves of the Thai basil. The odd thin stem is fine, but we want to mainly use the leaves.
Place everything in a chopper, with only 2 tablespoons of the lime juice.
Chop to a fine paste. Taste, and add more salt, sugar and lime juice as necessary and if you think it needs some. You are aiming for a hot, sour and slightly sweet flavour.
Transfer to a clean jar and keep in the fridge for up to 2 weeks. It can also be used immediately.
Video
Notes
Per serving is estimated at 1 tablespoon, which is about (20 g/0.7 oz).