In a skillet, brown sausage, beef and onion. Remove from the heat drain. Remove the centers from the tops and bottoms of each bun. Tear removed bread into small pieces add to skillet. Set buns aside.
Stir remaining ingredients into sausage mixture. Spoon about 1⁄3 cupful onto the bottom of each bun replace tops. Wrap individually in heavy duty foil. Bake at 350°F for 20 minutes or until heated through or freeze for up to 3 months. To use frozen sandwiches: Bake at 350°F for 35 minutes or until heated through.