Boil potatoes, peel and mash into a fine paste. Add half the butter taken, add a tsp of salt to the mashed potatoes and mix well. Add boneless fish pieces, ginger-garlic paste, maida flour, onion paste, chopped green chilies, cashew paste, red chilly powder and sufficient salt to the above. Prepare a thick dough and mix and knead well. Prepare circular and flat cutlets of about three inch size. Take refined oil in a deep bottomed pan and heat. Roll the cutlets in beaten egg and corn flour. Add one by one to the boiling oil carefully and deep fry until they turn dark brown. Apply remaining butter to all the bread slices on both sides and slightly fry them in a flat frying pan. Serve the cutlets and the bread slices hot along with hot and sweet sauce.