A lovely, delicate curry inspired by the Christian dishes and ingredients of Kerala. It is easy, quick and great for family (without the chilli) or friends. The cashew nuts are lightly roasted, then added to the prawns, but you can leave them out. The Keralans would use a thin extract of coconut milk to cook the prawns, then add thicker coconut milk at the end. Canned coconut milk should have its cream accumulated at the top, so spoon this off and stir it in at the end; it adds a lovely aroma and richness.