Drizzle olive oil into a large skillet and heat over medium-high heat until shimmering.

Add sliced onions and green bell peppers to the skillet, sauté for 3-5 minutes until softened. If using, add mushrooms and cook for another 3 minutes.

Push vegetables to one side of the skillet, and add ground beef. Cook for 5-7 minutes until browned.

Sprinkle garlic powder, Worcestershire sauce, salt, and black pepper over the beef. Cook for 2 more minutes.

Lower heat and layer provolone cheese over the beef mixture. Cover and melt for 2-3 minutes.

Slice hoagie rolls lengthwise without cutting through, creating a pocket.

Spoon beef and veggie mixture into rolls, adding extras if desired.

Toast filled rolls in skillet for a minute if desired, then serve hot.