1. Marinate Prawns with turmeric powder, chilli powder, pepper powder and salt and keep it aside. Slice the onion very thin. Wash the rice, drain the water completely and add the said quantity water, salt, a little lemon juice, all the whole spices,1 tablespoon butter/ghee and microwave it at high for 15 minutes. So see to it that it is cooked till grains remain separate.
2. Grind together green chillies, garlic, ginger and grated coconut into a coarse paste adding curd.
3. Heat a little ghee in a wok. Fry the prawns to a golden brown tinge.(keep a few fried prawns for garnishing). To the fried prawns, in the same oil ,add 3 onions chopped and saute them to a translucent texture. Add tomato, ground paste, chopped coriander leaves and mint leaves and the lemon juice. Cook till the masala reduces Add the Eastern Garam masala. Keep stirring so that it doesn't stick to the bottom of the vessel.
4. Now add the cooked rice to this reduced prawn gravy, close it with a heavy lid and cook on slow fire for 3-4 minutes or transfer it to a microwaveable vessel and layer rice on top and microwave it at high for 4minutes. Finally mix everything well and garnish with fried prawns, roasted cashews, raisins and caramelised onion (1 onion remaining) and serve it hot with Onion Raita.