Mix the mutton pieces with vinegar and salt. Roast rest of the ingredients in section A and grind together to a fine powder. Add to the mutton and set aside.
Grate the coconut and extract 1 cup thick milk and 2 cups of thin milk.
Wash the rice, drain well. Add the thin milk and 5 cups of water. Add rampe leaves (in section B) and salt to taste.
Cook till all the liquid is absorbed. Spread on a wide tray and allow to cool.
Heat Ghee (section C) fry cashew nuts and raisins, drain and reserve.
Add rampe, curry leaves and onion to the remaining Ghee in the pan. Fry till onion is golden brown. Add the mutton mixture, fry for 5 minutes. Add 1 cup of water and simmer till the mutton is cooked and almost dry.
Add the cooked rice to the mutton in the pan. Pour the thick coconut milk on top. Sprinkle with the powdered spices. Mix gently. Dot with butter and leave covered on a low flame for 8-10 minutes till the coconut milk is absorbed. Alternately, place the mutton and rice mixture in an oven proof dish. Cover with aluminium foil and bake in a hot oven (200 degrees centigrade) for 20 minutes
Transfer the biryani to a serving dish and serve garnished with fried cashew nuts, raisins, hard-boiled egg halves and potato wafers.