Melt butter in a large skillet over medium-high heat; add onion, bell pepper, and mushrooms, and saut 13 minutes or until onions are golden brown.
Add steak strips and garlic; saut 3 minutes or until thoroughly heated. Stir in dressing, and, if desired, crushed red pepper. Season with salt and black pepper to taste.
Arrange steak mixture evenly on bottom roll halves; top with cheese and remaining roll halves. Arrange on a baking sheet.