Philly Cheese Steak Sandwich

Name: Philly Cheese Steak Sandwich
Ingredients: 2 tablespoons minced fresh oregano, or 2 teaspoons dried; 1/4 cup reduced-sodium chicken broth; 1 tablespoon all-purpose flour; 3 ounces thinly sliced reduced-fat provolone cheese; 1/2 teaspoon salt; 1 red or green bell pepper, sliced; 4 whole-wheat buns, split and toasted; 1 medium onion, sliced; 8 ounces mushrooms, sliced; 1/2 teaspoon freshly ground pepper; 1/2 cup sliced hot banana peppers, (optional); 1 pound sirloin steak, trimmed and thinly sliced (see Kitchen Tip); 2 teaspoons extra-virgin olive oil