Marinate the Mutton with ginger garlic paste, yogurt, turmeric powder, mustard oil, red chilli powder, salt and leave it overnight in the refrigerator.
Dry roast the spices to be ground in powder. Namely fennel seeds, black peppercorn, coriander and cumin seeds and grind them to a fine powder using a mixer.
Peel the potatoes and cut them into half. Lightly fry the potatoes till they are slight golden brown in colour. Remove and keep aside
In a heavy bottom kadhai or pan, Heat the mustard oil. Once the oil is hot, add the whole spices and sautee for 2-3 minutes till the spices are fragrant.
Add the ginger and garlic pastes and sauté till further for couple of minutes till the raw smell is gone.
Add the sliced onions along with a pinch of salt and sauté till they turn golden brown. Keep stirring this frequently and do it on a slow flame to get uniform browning.
Add the tomato puree, green chilli, turmeric powder, redchili powder along with the prepared masala powder. Saute till oil leaves the sides. Again do this on low flame and keep stirring, patience really is the key here.
Add the marinated mutton and let it cook on medium heat till the meat has realesed it’s juices and has and oil layer on the top.
At this point, add the fried potatoes and water. If you are using a slow cooker, add the whole thing to the slow cooker and let it cook on low heat for 6 hours. It is pretty much all right on it’s own but you can stir it in between a couple of times if you are around.
If you are using a pressure cooker, cook on high for one whistle and then reduce the flame and cook further for 12-15 minutes. Let the pressure release completely before you open the cooker.
If you are cooking on stove top, cook on low heat for 3-4 hours. Make sure you stir it every 5-6 minutes so that it doesn’t stick to the bottom.
Once the curry is ready and mutton cooked, add the garam masalas powder and ghee. Cover the curry and let it absorb the flavours before serving