Soak rice in three cups of water for half an hour. Drain and set aside. Take yoghurt in a bowl, add half the ginger paste, half the garlic paste, half the green chilli paste and salt to taste.
Mix well and marinate in it. Heat sufficient oil in a kadai and deep-fry half the sliced onions till brown and crisp. Drain and place on absorbent paper.
Heat ghee in a pan and add bay leaf, black peppercorns, black cardamoms, green cardamoms, star anise, cinnamon and the remaining half of the sliced onions.
Sauté for two minutes. Add remaining ginger paste, garlic paste, green chilli paste. Stir well and add rice.
Add turmeric powder, red chilli powder, garam masala powder, coriander powder and saffron strands. Mix well add marinated prawns.
Add salt, lemon juice, coriander and mint leaves. Stir and add fried onions. Add about 1 1/2 cups of hot water.
Cover and cook on low heat till rice is soft & fluffy. Remove from heat and allow to rest, covered, for five to ten minutes.
Serve directly from the cooking pan at the dining table in order to retain maximum flavour.