Rinse the fish cutlets and trim away the fins with a pair of scissors. Still using the scissors, snip out the centre bone from each cutlet to leave a space for the stuffing. Place the cutlets in a well-buttered baking dish and set aside while preparing the stuffing.
Combine the breadcrumbs, suet and parsley in a small basin. Add a seasoning of salt and pepper. Lightly beat the egg and t