I clean the mutton really well, until the water no longer is red (I don't do blood). I pressure cooker it with some water, salt, a bit of tumeric. I don't use the water after its cooked, cause its FAT :), but you can if you would like. If you don't have a pressure cooker, marinate the washed mutton in some garam masala, garlic and ginger paste for a little while

Cut the Onions, tomatoes and green chillies

Heat some oil in a deep pot. add the cumin seeds, followed by the onions, green chillies, pepper corns and cloves. Cook it until the onions become transparent. Then add the tomatoes and some ginger and garlic paste. I just add a bit even if there is some in the marinade, but you can always opt out. Add a  tbsp of garam masala, and let it cook really well. You might want to add some water to get a nice gravy

Add the meat next. Add some water if you want more gravy, some more garam masala (if needed) and the required amount of salt

Notes:

You can serve this with rice or roti or chapathi