Cook it in whatever way you like either in the pressure cooker and pot. You can also add few drops of oil to the rice pot to keep the rice grainy. Rice should be grainy fully cooked but not mushy.wash prawns in vinegar to remove the fishy smell. Drain them completely and set aside. you can marinate prawns with ginger garlic paste, garam masala, coriander powder, red chili powder, salt and turmeric.