Step 1

Cut beef into thin slices; sprinkle with salt and pepper.

Step 2

Heat a large nonstick skillet over medium-high heat. Add 1 teaspoon oil to pan; swirl to coat. Add beef to pan; sauté 2 minutes or until beef loses its pink color, stirring constantly. Remove beef from pan. Add 1 teaspoon oil to pan. Add onion; sauté 3 minutes. Add mushrooms, bell pepper, and garlic; sauté 6 minutes. Return beef to pan; sauté 1 minute or until thoroughly heated and vegetables are tender. Remove from heat. Stir in Worcestershire and soy sauce; keep warm.

Step 3

Place flour in a small saucepan; gradually add milk, stirring with a whisk until blended. Bring to a simmer over medium heat; cook 1 minute or until slightly thick. Remove from heat. Add cheeses and mustard, stirring until smooth. Keep warm (mixture will thicken as it cools).

Step 4

Hollow out top and bottom halves of hoagie rolls, leaving a 1/2-inch-thick shell; reserve torn bread for another use. Divide beef mixture evenly among bottom halves of hoagie rolls. Drizzle sauce evenly over beef mixture; replace top halves.