Combine meat with yogurt and all the spices and leave to marinate for 2-3 hours. When you're ready to cook, fry the onion in a large stew pot with half the butter. Add the marinated meat mixture and simmer until liquid is slightly thickened. Set aside.
Meanwhile, in separate pots, using enough eater to cover , boil rice and lentils for about 15 minutes. Drain. To assemble the biryani, layer the ingredients in the pot : rice first, then meat, more rice, lentils, and meat again. Continue in this pattern until everything has been used. Melt the remaining butter and pour over the mixture along with 1/2 cup water. Cover the pot and simmer on lowest heat for one hour. Serve on a platter, garnished with parsley or coriander and egg slices.
(picture : google image)