Heat grill. When ready to grill, remove steak from marinade; discard marinade. Place steak on gas grill over medium heat or on charcoal grill 4 to 6 inches from medium coals. Cook 12 to 15 minutes or until of desired doneness, turning once. Spread both sides of bread slices with 2 tablespoons of the butter. To toast, place on grill during last 2 to 4 minutes of cooking time. Turn once.