6 slices bacon
1 med. onion, sliced and separated into rings
4 lg. frankfurters or knockwurst
1 lb. loaf rye or pumpernickel bread, sliced in half lengthwise
Horseradish mustard or prepared mustard
4 slices Swiss cheese
4 slices American cheese

In a large skillet cook bacon until crisp. Drain bacon on paper towels. Reserve 2 tbsp. drippings. Cook onion in bacon drippings in skillet until tender. Meanwhile, cook frankfurters, covered, in a small amount of boiling water for 5 minutes or until heated through. Drain.

Toast bread under broiler. To assemble sandwiches, spread bottom half of loaf with mustard. Cut frankfurters in half lengthwise, cutting to but not through the other side. Place cut side down on top of mustard. Top with bacon. Alternate and overlap cheeses on top of bacon. Top with cooked onion. Place under broiler for about 1 minute or until cheese is melted. Top with top half of bread. Cut into 4 pieces. Makes 4 servings.