Savory Steak With Mushrooms

-  1-lb. boneless flank or sirloin steak -  1 package (10 oz.) mushrooms, quartered -  1/4 cup I Can't Believe It's Not Butter!® Spread -  2 shallots or 1 small onion, chopped -  2 cloves garlic, finely chopped -  2 Tbsp. balsamic vinegar -  1/2 tsp. salt -  1/2 tsp. ground black pepper

Arrange steak in broiler pan, without the rack; score (lightly cut) steak. Arrange mushrooms around steak; set aside.

Combine remaining ingredients in small bowl. Brush 1/2 of the mixture over steak and mushrooms. Broil steak, turning once and brushing with remaining mixture, until steak is desired doneness. Serve steak with pan juices and mushrooms.