MIX the ingredients for peri-peri sauce together in a bottle and shake well. You can make the sauce ahead and store it in the fridge; the flavor improves with age, reaching its peak at two weeks.
SLIT prawns down their backs and de-vein. Leave heads on (or remove them if you prefer).
HEAT the butter gently and add the garlic and lemon juice. Don't let the garlic burn. Add prawns and peri-peri
sauce (cook in one or two batches, depending on the size of your frying pan). Shake to make sure you get some of the chili and garlic.
SIZZLE for 4-5 minutes, turning frequently, until cooked. Season with salt and pepper and tip into a warm serving
GARNISH, if you wish, with chopped fresh parsley. Serve with rice or bread and butter.