1. Prepare rice: Rinse and soak the rice for 30 minutes. Drain and set aside.
2. Cook rice: Boil the rice in water until it's 70% cooked. Drain and set aside.
3. Marinate prawns: Marinate the prawns with ginger-garlic paste, biryani masala, and salt for 15-30 minutes.
4. Cook prawns: Heat ghee or oil in a pan and cook the marinated prawns until they're pink and cooked through.
5. Layer biryani: In a large pot or Dutch oven, create a layer of cooked rice. Add a layer of cooked prawns on top. Repeat this process until all the ingredients are used up.
6. Dum cooking: Cover the pot with a tight-fitting lid and cook on low heat for 10-15 minutes.
7. Serve: Garnish with fresh cilantro and serve hot.