Combine all ingredients except oil in the "for marination" section till well combined. Allow to marinate for at least one hour.
Fry the marinated prawns in the coconut oil flipping the sides, till browned and almost 75% cooked. Set aside.
In a saucepan, we can start making the masala by heating the coconut oil. Add the onions and chillies and saute till the onions are soft.
Add the tomatoes and cook till they are all mashed up.
Add in the turmeric and red chilli powder and saute well. Continue to cook till the tomatoes are totally cooked.
Add in the fried prawns and cook for a few more minutes. Sprinkle in some water if the masala looks too dry.
Add in the garam masala powder, mint leaves, coriander leaves and seasoning. Mix well and switch off.
While the masala is getting cooked, make the rice. Heat the ghee and fry the whole spices.
Add the curry leaves and onion and saute till witled.
Add the water and bring it to boil. Add salt.
Add in the drained rice and keep on high flame till the water comes to a rolling boil.
Keep it on the lowest flame possible and cook on closed lid till the water is absorbed and the rice is almost cooked - there will still be a bite. Switch off.
For the dum ingredients, heat the coconut oil and ghee in a deep frying pan.
Add the sliced onions with a sprinkle of salt and fry till browned. Drain and set aside.
Fry the cashews and then the raisins and set aside. Keep the frying oil aside.
Keep a tawa to heat on low flame. In a large saucepan, sprinkle a spoon of the leftover oil. Spread a thin layer of rice.
Add the whole prawn masala on top. Sprinkle half fried onions, cashewnuts, raisins, chopped mint and coriander leaves and garam masala.
Layer the remaining rice over the masala. Sprinkle the remaining dum ingredients, the leftover fried oil, and the rosewater.
Cover with foil and close the lid tightly. Keep the saucepan on top of the hot tawa.
Keep on high flame for 5 minutes, then reduce to the lowest and keep it for 20 minutes. Switch off.
Open the lid and remove the foil at the time of serving. Mix well and serve hot with raita and pickle.