Open the oysters. Keep 6 oysters aside in the refrigerator. Put the whiting fillets, 24 oysters, cream, butter, egg whites, salt and pepper through an electric mixer. Roll out the pastry. Cut into 12 rectangles, about 3 x 2 inches. Arrange a layer of stuffing on 6 of these rectangles. Top each with one of the oysters kept aside. Cover with the other rectangles. Press to stick the edges. Use the tip ofa knife to make incisions on the edges of both layers of pastry. Glaze with the beaten egg. Bake in a hot oven (400F) for about 30 minutes. Serve hot.
