Heat Mustard Oil in a Pressure Cooker till steaming hot and fumes are coming out.
Switch off the gas till the oil is comparatively cooler, add all the garlic and ginger, fry for ½ min and add the mutton pieces. Put 2tsp of turmeric, all the red chilli powder and stir fry till all the water dries up.
Put all the tomatoes and onions in a grinder and make a fine paste.
In a separate pan, pan fry the boiled potatoes cut into halves, till they have a brownish tinge.
Put all the paste into the pressure cooker and put the remaining turmeric in the cooker. Add salt, cover with a plate and let the whole thing cook until the paste leaves the vessel and oil starts coming at the top. May be, you would require to uncover the lid and stir for 2-3 times in between.
Once all the paste and mutton is almost cooked, add the garam masala , washed keema, boiled potatoes, water as per required. Not much would be required as the gravy should be thick (approx. 1litre should be sufficient). Close the pressure cooker and cook till 3 whistles.
Open, let the preparation cool for 10minutes. Serve in serving dish and garnish with sliced tomatoes and chopped coriander leaves.
If the preparation is cooled for about 10min, it will taste and appear richer both.
Serve this with Naan or Roti. Not suggested with rice as the gravy would be thick.
Soak the keema in plain water for 30minutes while you are cooking the firt part, drain the water completely using a sieve, keema would be softer and cleaner definitely