Heat broiler. Season steak with ½ teaspoon salt and ¼ teaspoon pepper and place on a broilerproof rimmed baking sheet.
Broil the steak, 4 to 5 minutes per side for medium-rare. Let rest for 5 minutes, then cut into ½-inch pieces.
Meanwhile, in a large bowl, combine the romaine, cabbage, beans, peppers, and parsley. Add the steak and dressing and toss to combine.