Instructions :
1. Set oven temperature to 375 degrees.
2. Season beef with part of the salt, pepper, and oil.
3. Heat skillet intensely, then sear beef undisturbed for 2 minutes.
4. Mix in Worcestershire sauce, stir, then take out beef.
5. Introduce butter, bell peppers, onions, and mushrooms to skillet with remaining seasoning, cooking until golden for 3-4 minutes.
6. Smear mayonnaise on each bread half.
7. Layer with half of the cheese, follow with beef, veggies, and remaining cheese.
8. Place on the middle oven rack, baking for 15 minutes until crisply browned