Combine first 4 ingredients in a small bowl; stir well.
Place steak on a broiler pan coated with cooking spray. Spoon half of mustard mixture evenly over steak, and broil 4 minutes. Turn steak, and spread remaining mustard mixture over steak. Broil 3 minutes or until desired degree of doneness. Place steak on a serving platter; sprinkle with parsley and pepper.