Philly Cheesesteak

Name: Philly Cheesesteak
Ingredients: 1 (12-ounce) flank steak, trimmed; ¼ teaspoon kosher salt; ¼ teaspoon freshly ground black pepper; 2 teaspoons extra-virgin olive oil, divided; 1 cup thinly sliced onion; 2 (5-inch) portobello mushroom caps, sliced; 1 ½ cups thinly sliced green bell pepper; 2 teaspoons minced garlic; ½ teaspoon Worcestershire sauce; ½ teaspoon lower-sodium soy sauce; 2 teaspoons all-purpose flour; ½ cup 1% low-fat milk; 1 ounce provolone cheese (about 1/4 cup), torn into small pieces; 2 tablespoons grated fresh Parmigiano-Reggiano cheese; ¼ teaspoon dry mustard; 4 (3-ounce) hoagie rolls, toasted