Two teaspoonfuls of chopped parsley. Salt and pepper.
Wash and dry the fish. Lay four slices of the bacon in a buttered bag; on these put two or three slices of onion, lay the fish on these. Melt the butter, mix with it the flour and a careful seasoning of salt and pepper. Spread this on top of the fish. Cover it with the rest of the bacon cut in strips. Fold and secure the edges of the bag, put it on the grid in the oven, and bake from twenty to thirty minutes.