Heat ghee in a pressure cooker and fry all the whole spices for a few seconds.
Fry sliced onion with mint leaves and green chilies till onion turns light golden followed by ginger & garlic paste. Saute for 1 minute or till the raw smell disappears.
Now add tomato, red chili powder, coriander powder, turmeric powder, and yogurt. Fry for 1 minute and then add mutton pieces along with enough salt. Mix well and cook on high heat for a minute.
Reduce the heat and add 2 or 3 cups of water or according to the consistency, you need.
Place the lid and cook the curry on medium to low heat for 10 minutes.
Release the pressure from the cooker and open the lid carefully. The mutton will be half cooked at this point. Add potatoes and close the lid. Cook for another 15 minutes.
When the mutton is fully done, add garam masala powder and coriander leaves. Taste and adjust the salt and also the consistency of the curry.
Serve hot with rice or roti.