1 tbsp. butter
1 (8 oz.) can mushroom stems and pieces
1/2 med. onion, diced
2 lb. ground beef
1/2 shredded baking potato
1 egg
1 tbsp. Worcestershire sauce
1 tsp. salt
1/2 tsp. pepper
1/4 c. catsup
1/2 tbsp. flour
Remaining onion, diced

Brown mushroom stems and pieces and onion in butter. Mix together rest of ingredients. Divide ground beef into 12 even portions. Make patty and form edge (cup shape). Place mushroom mixture in center. Top with another patty. Wrap each double patty with 2 slices of bacon and fasten with toothpicks. Broil 10 to 15 minutes on each side, 6 to 8 inches from heat. Serves 6.