Brown ground beef and onion in a large skillet; drain off fat. Add cabbage, soup mix, and pepper during the last five minutes of cooking. Set aside. Roll one load of bread dough into an 8x16-inch rectangle, then cut into eight 4-inch squares. Spoon mixture into center of each square; bring up diagonal points, pinching edges closed. Let cabbage rolls rise on greased cookie sheet for about 10 minutes. Preheat the oven to 350 degrees. Bake 20 minutes or until brown. Brush tops of warm rolls with bitter or margarine if desired. Repeat process with second loaf of bread and remaining mixture. This can be frozen (after baking) and reheated 1 1/2 minutes in a microwave oven.