In a skillet, cook bacon until crisp. Remove to paper towels to drain.
Saute’ mushrooms and onion in the drippings until tender. Transfer to a bowl and add the bacon.
In another bowl, combine the egg, Worcestershire sauce, seasoned salt, pepper and horseradish; add beef and mix.
Shape into six 1/4 inch thick patties.
Divide bacon mixture among three patties. Top with cheese.
Place remaining patties on top of each and seal edges.
Grill, uncovered, over medium-hot heat for 12-14 minutes or until meat juices run clear, turning once. Serve on buns. Yield: 3 servings.