1. Place the prawns in a large bowl, and sprinkle with turmeric, paprika and salt. Set aside.
2. In a food processor, blitz together the garlic & ginger and green chilli pastes, onion, and the garam masala, coriander, cumin and chilli powders to form a smooth, creamy paste.
3. Heat some oil in a large pan and stir fry the paste until fragrant. Turn down the heat and simmer for 5 minutes or so, until the oil starts to split from the sauce, stirring occasionally.
4. Add the coconut milk, and bring to the boil. Add sugar and salt, to taste.
5. Add the King Prawns and cook for a few minutes only, until they turn from grey and translucent to pink and opaque. Do not overcook, as they will continue to cook in the hot sauce.
6. Serve with steaming hot Jeera Rice or Basmati Rice.