Heat olive oil in a large skillet over medium heat.
Add onion and bell pepper and cook for 4–5 minutes until softened. Remove and set aside.
In the same skillet, add ground beef and cook until browned, breaking it apart as it cooks. Drain excess grease if needed.
Season the beef with garlic powder, Worcestershire sauce, salt, and black pepper.
Return onions and peppers to the skillet and stir to combine.
Reduce heat to low. Place provolone cheese slices over the beef mixture. Cover and let cheese melt for 1–2 minutes.
Lightly toast hoagie rolls if desired.
Spoon the cheesy beef mixture into the rolls and serve hot.