Peel and chop half the onions into fine slices and the other half into thick slices.
Marinate the mutton pieces in ginger, garlic, vinegar and salt, and keep aside for 1 hour.
Pressure cook the meat pieces with 1 cup of water till they are just tender. Reserve the marinade.
Hence the oil in a pan and fry the fine slices till they are translucent.
Mix in the dry red chillies, mutton cubes with marinade the rest of the onions and the chilli paste.
Fry these together on a medium heat, stirring from time to time. You may need to add 2 tsp of water if the onions begin to stick to the bottom. Fry the meat and the onions till the thickly chopped onions are cooked and attain a light golden color.
Mix in the sugar and the vinegar and stir-fry for another 2-3 minutes till the gravy is absolutely dry.
Serve with parathas.