Line the air fryer basket with parchment paper (preferably pre-cut basket liners for best results).
Add the butter, sliced onions, and bell peppers to the basket. Air fry at 400°F (200°C) for 3 minutes, then stir. Air fry for another 2 minutes until softened. Remove and set aside.
1 large onion, 1 tablespoon butter, 1 small green bell pepper
Add the sliced steak to the basket. Drizzle with 1 tablespoon olive oil and season with salt, pepper, and garlic powder. Air fry for 7 minutes, flipping or stirring halfway through.
1 pound ribeye steak, 1 tablespoon olive oil, Salt and pepper, ½ teaspoon garlic powder
Return the onions and peppers to the steak in the basket. Lay provolone slices over the top and air fry for an additional 5 minutes, or until the cheese is fully melted.
4 slices provolone cheese
Place hoagie rolls in the air fryer (brushed with butter and no filling) and toast at 350°F (180°C) for about 5 minutes, or until golden.
4 hoagie rolls, 1 tablespoon butter
Load each toasted roll with the hot, cheesy steak mixture. Serve immediately.