Combine all ingredients except water in a powerful blender or food processor.
Blend to a fine paste, scraping down the sides as you go. Add the water as required to help it blend.
Use this paste to make green curry chicken. Please see my recipe below.
Notes
Spiciness - The spiciness comes from the Thai green chillies. If you want a very mild curry, skip the Thai chilies altogether, for a mild curry, just use 1. Using 6 chilies makes this pretty spicy, but not outrageously so - but we do like our green curry spicy.Lemongrass - Peel the tough green outer layers and use the white softer part. The outer reedy layers can't be finely chopped.Galangal looks like ginger but is more citrusy and harder. Feel free to substitute ginger if you can't find galangal.