1. Cut the mutton into about 1.25 cm. (1/2") thick slices. Flatten with a steak hammer or a wooden roller. Soak in a mixture of vinegar, sliced garlic, finely chopped ginger and chilli powder.
2. Set aside for 10 to 12 hours (preferably in a refrigerator). Remove from the marinade. Add salt.
3. Heat fat. Fry the chops over a quick fire for a few minutes, on either side. Reduce heat. Sprinkle over with salt and pepper and cook for another 5 to 10 minutes.
4. Remove on to a hot plate. Fry roundels of onions in remaining fat and place over the chops.
5. Prepare a gravy by adding about half a cup of warm water to the dripping; add more seasoning and cook till gravy is brown and fairly thick.