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 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 strips mixture evenly on bottom roll halves; top with cheese and remaining roll halves. Arrange on a baking sheet.
Bake at 400 for 8 minutes or until buns are toasted and cheese is melted.