London Broil Stuffed with Mushrooms & Cheese

4 pound piece London broil
3 tablespoons butter
1/2 pound fresh mushrooms, sliced
4 tablespoons crumbled Blue, or Cheddar
2 cloves garlic, crushed
2 teaspoons each of salt & pepper

Have butcher cut lengthwise pocket in steak. Saute mushrooms in 1 tablespoon butter for 2 minutes. Combine mushrooms, cheese, remaining 2 tablespoons butter, garlic, salt & pepper. Stuff pocket with mushroom mixture. Fasten with skewers or toothpicks. Sprinkle steak with additional salt & pepper. Refrigerate until shortly before serving time. Broil about 3 inches from heat for 5 to 6 minutes on each side depending on size and thickness of steak. Place on warmed platter. Slice in thin diagonal slices against the grain. serves 4-5.