Preheat the Blackstone Grill to medium-high heat and lightly grease the surface with cooking spray or oil.

In a large bowl, combine the thinly sliced steak, avocado oil, Italian seasoning, garlic powder, salt, and pepper. Toss the steak to coat it evenly with the seasonings.

Place the seasoned steak slices on the hot Blackstone Grill and cook for 2-3 minutes on each side, or until the steak reaches your desired doneness. Remove the steak from the grill and set it aside on a plate.

Lower the heat on the Blackstone Grill to medium. Add the sliced onions and green bell peppers to the grill and cook, stirring occasionally, until they are softened and lightly caramelized, about 5-7 minutes.

Lightly butter the cut sides of the hoagie rolls and place them on the Blackstone Grill, cut-side down. Toast the rolls until they are lightly golden and crispy, about 1-2 minutes.

To assemble the sandwiches, place two slices of provolone cheese on the bottom half of each toasted hoagie roll. Add a layer of the cooked steak slices, followed by the sautéed onions, green bell peppers, and pepperoncini peppers.

Place the top half of the toasted hoagie roll on the peppers to complete the sandwich. Enjoy!