This is from “Madhur Jaffrey’s Cookbook”.
Peel and devein the prawns then wash, pat dry and set aside.
Put the red pepper, onion and nuts into a food processor and blend thoroughly then put the paste into a bowl.
Heat 3 tbsps oil in a frying pan over a medium heat. Put in the mustard seeds and when they begin to pop add the garlic. Stir once and add the prawns then fry for 2-3 minutes before removing with a slotted spoon.
Add 1 tbsp oil to the wok and put in the red pepper paste. Stir and fry for 4-5 minutes until the sauce looks quite dry. Add 1/4 tsp salt, the cayenne and paprika. Stir once then add the prawns and 4 tbsps water.
Lower the heat and stir gently for one minute- you should have a very thick sauce.
Serve immediately with a green salad and rice.