Grind the ginger, garlic and chillies to a paste. Mix into the curd, along with the garam masala, coriander, cumin,. nutmeg, mace, turmeric, salt and chilli powder. Mix the mutton into the curd and set aside for 1 hour. Boil the dual in water till very soft, mash to a paste and pass through a tine sieve. Now heat the ghee and fry the onions till soft. Add the mutton, cover tight and cook till the mutton turns- dry. Then fry to a red color. Cover with hot water and cook till the mutton turns tender and almost dry. Remove from fire. Now heat 2 tblsps of ghee in a separate vessel, and add the tomatoes, frying till soft. Mix in the dad, pouring enough hot Water till it turns creamy. Add the mutton and cook for 15 minutes. Serve hot, garnished with chopped coriander leaves.