Rinse the rice and then soak in water for 30 minutes.
Soak mushrooms in boiled water for about 15 to 20 minutes. Remove the mushrooms and carefully dry on a kitchen towel. Cut the mushrooms into half or even smaller pieces if necessary. Set aside.
Ina deep suacepan on medium heat, and add 2 tablespoon of ghee. When hot, add the cumin. After a few seconds, add spices— bay leaves, black pepper, cloves, green cardamom pod, cinnamon, mace, coriander powder and cumin powder. Stir for a few minutes. Add rice and stir well (for four minutes) to coat it evenly in the oil and spices. Add salt to taste and add four cups of water. Stir and bring to a boil. Cover with a tight fitting lid, reduce the heat and let it simmer for 10 to 15 minutes. The rice should be par cooked. Drain well and set aside.
Place a pan on medium heat and add 2 tablespoons of the ghee. When hot, add the onions and stir frytill the onions just start to brown around the edges. Add ginger and garlic. Cook for 2 to 3 minutes and then add the rest of the spices—red chili powder, turmeric, coriander powder, cumin powder and garam masala. Stir fry for a few minutes. Let the spices cook for a few more minutes and then add the tomato puree. Let it cook for 5 to 6 minutes and then reduce the heat to slowly whisk in the yogurt.
Stir well so that all of the ingredients are combined. Now add about half of the mint leaves into the mixture. Add salt to taste, and cook for just another minute or so. Turn off the heat.
In a well oiled casserole with a tight fitting lid, arrange the rice and mushroom mixture in layers. Both the top and bottom layers should be rice. Next, add the remaining ghee, sauteed onion, remaining mint, nuts and raisins along with their liquid and the saffron/milk mixture.
Cover the dish tightly with the lid sealed with dough and cook on dum for 10 minutes.
Sprinkle with toasted cashew pieces and any remaining mint leaves. Garnish with coriander leaves.
Serve hot with yoghurt & onion salad.