Wash and chop the onion, slice the mushrooms, and dice the green bell pepper into strips. Set aside.

In a large skillet, heat olive oil over high heat. Add the chopped onion, mushrooms, and bell peppers. Sauté for about 10 minutes until tender.

In the same skillet, add more olive oil if necessary, then add the shaved ribeye beef. Cook for about 5 minutes, breaking it up until browned. Top with provolone cheese and cover for 1 minute to melt.

Preheat your air fryer or oven to 400°F (200°C). Spread softened butter on the inside of the bread rolls, then sprinkle with garlic powder and parsley. Toast for 2-3 minutes until golden.

Assemble by filling each toasted roll with the beef and vegetable mixture, adding any desired toppings.

Cut the sandwiches in half and serve immediately while hot.