Heat ghee in a heavy-bottomed pot on medium heat.
Add shahi jeera, bay leaves, cinnamon, star anise, green cardamom, cloves, and black peppercorns, and saute for about 30 seconds.
Add sliced onion, and saute until it turns golden brown.
Next, add coarsely crushed ginger-garlic paste and green chilies, and saute until fragrant.
Add coriander powder, cumin powder, red chili powder, garam masala, and turmeric.
Saute for about 30 seconds. Add a few splashes of water if needed to prevent the spices from sticking to the bottom of the pot.
Add chopped tomatoes and salt to taste. Mix well, and cook until the tomatoes turn mushy and fat separates from the sides. You can add a few tablespoons of water if needed to cook the tomatoes.
Add the marinated prawns, and cook on medium-high heat just until it turns opaque, about 1 minute.
Add half of the chopped coriander leaves, and mix.