Chop the onions finely. Melt the fat in a broad shallow saucepan. Add onions, and brown lightly. Cut meat in small pieces, and add to onions. Stir well until all pieces are thoroughly seared. Remove skins from tomatoes by pouring boiling water over them, the skins can then be easily removed, chop up the flesh into small pieces and add to meat. Add the skin of the red chilli finely chopped, cover and simmer on the side of the stove for about 2 hr. Just before serving, add sugar, salt and pepper.