Gut the herrings through the gills, remove and save the roe. Place 3 1/2 oz strong yellow mustard in a bowl, adding a pinch of Cayenne pepper. With a knife, cut 2 or 3 slits on the haddocks. Brush the roe with the mustard, place back into the fish then rub the haddocks with the mustard. Roll the fish in the bread crumbs, place on the grilling rack. Baste while cooking, by brushing the fish with some melted butter. Halfway cooked, carefully turn the fish over and baste with butter. Serve in the English style with fries or boiled potatoes.
