This recipe is for mullets, but any small, plump fish may be used. Make a paper case for each fish with a sheet of well-oiled notepaper and put the cases into the oven for a few minutes to harden. Sprinkle the under sides of the fish with pepper and salt and lay them in their cases with a small piece of butter under and over each. Place the cases in a baking-dish and cook for about twenty minutes in the oven, or more if the fish are otherwise than small. Sprinkle well with lemon juice just before serving.