In a large skillet, add a drizzle of olive oil and heat over medium-high.

Add the sliced onions and bell peppers. Sauté for about 3-5 minutes until they are tender.

If using, add mushrooms and cook for an additional 3 minutes.

Push the vegetables to the side of the skillet and add the ground beef. Break it apart and cook until no longer pink, about 5-7 minutes.

Stir in garlic powder, Worcestershire sauce, salt, and pepper. Mix everything together for about 2 minutes.

Reduce the heat to low. Place a slice of cheese over the beef mixture. Cover the skillet with a lid and allow the cheese to melt, about 2-3 minutes.

While the cheese is melting, slice the hoagie rolls lengthwise without cutting all the way through.

Once the cheese has melted, spoon the beef and vegetable mixture into each roll.

Optionally, toast the rolls for added texture before serving.