Score the fish on the back with a knife, and season then with salt and cayenne pepper. Cut some small onions in round slices, and chop fine a bunch of parsley. Put some butter into a frying-pan over the fire, and when it is boiling hot lay in the fish. When they are about half done put the onions and parsley into the pan. Keep turning the fish that the onions and parsley may adhere to both sides. When quite done, put them into the dish in which they are to go to table, and garnish the edge of the dish with hard boiled eggs cut in round slices.
Make in the pan in which they have been fried, a gravy, by adding some butter rolled in flour, and a small quantity of vinegar. Pour it into the dish with the fish.