In a bowl, mix together beef, pork, sauerkraut, apple, caraway, salt and pepper. Form into 4 burger patties about 3 inches in diameter and 1 inch thick. Preheat a grill and oil grill grate well. Grill burgers about 3 minutes on each side for rare, 4 minutes for medium rare. Top with cheese in the last minute of cooking. (Or pan-fry burgers in oil or bacon fat over medium heat about 3 minutes on each side for rare, 4 minutes for medium rare, topping with cheese in the last few minutes of cooking.) Place each burger on the bottom of a baguette half and top with mustard and onion. Close with top half of baguette.
Recipe courtesy of the California Milk Advisory Board
Yield: 4 servings