Preheat the oven to 375°F (190°C) and line a large baking sheet with parchment paper.

Slice each hoagie roll lengthwise, being careful not to cut all the way through the back hinge.

Combine melted butter and garlic powder in a small bowl; brush the interior and exterior tops of the rolls with the mixture.

Distribute the meats evenly among the four rolls, layering 2 slices of ham, 2 slices of salami, and 4 slices of pepperoni in each.

Place 2 slices of provolone cheese over the meat in each sandwich.

Arrange the sandwiches on the prepared baking sheet and bake for 8 to 10 minutes, or until the cheese is fully melted and the bread edges are golden brown.

Remove from the oven and open each sandwich to add shredded lettuce, tomato slices, red onion, and banana peppers.

Drizzle with Italian vinaigrette and sprinkle with dried oregano before closing and serving immediately.