Arrange a rack in the middle of the oven and heat the oven to 350°F.
In a small bowl whisk together oregano, basil, and garlic powder. Set aside.
1 teaspoon dried oregano, 1 teaspoon dried basil, 1 teaspoon garlic powder
Place unsalted butter in a small, microwave-safe bowl and microwave until melted, 20 to 30 seconds. (Alternatively, melt butter in a small saucepan over medium heat.) Add garlic, onion powder, parsley and salt and pepper, and whisk to combine.
1/2 cup unsalted butter melted, 2 garlic cloves finely minced or grated, 1 teaspoon onion powder, 2 teaspoon dried parsley, Pinch of salt and pepper
Without separating the rolls, cut 1 package sweet dinner rolls in half horizontally with a serrated knife. Place the bottom half of the rolls in a 9x13-inch or 7x11-inch baking dish.
12 count package sweet dinner rolls or slider buns
Evenly spread tomato sauce on the button layer of the buns.
1/2 cup tomato sauce
Take the mixture of oregano, basil and garlic powder and evenly spread over the tomato sauce.
Sprinkle with mozzarella cheese.
2 cups mozzarella cheese
Arrange pepperoni slices evenly on the rolls, overlapping the slices as needed to completely cover. Layer the remaining 8 slices of provolone cheese over the pepperoni. Place the top half of the rolls over the cheese.
24 slices pepperoni, 8 slices Provolone Cheese
Brush the butter onto the top of the rolls.
Cover the baking dish tightly with aluminum foil.
Bake until the sandwich is heated through and the cheese melts, about 20 minutes. Uncover and bake until the rolls are lightly browned, 7 to 8 minutes.
Top with parmesan cheese and parsley.
¼ cup parmesan cheese, Fresh parsley
Transfer the slab to a cutting board, then cut into individual sliders with a serrated knife before serving.