Thaw your meatballs. This step is important so that the sliders cook easily in the oven.
Preheat oven to 350F
Cut the Hawaiian Rolls in half and lay the bottom half in a baking dish. I like to seperate each roll a head of time so that it makes it easier to pull apart when it is hot.
Put a layer of cheese on top of the rolls. If you are using Provolone slices, cut each slice of cheese in quarters and then put two quarters on top of the bread. Top with some shredded mozzarella.
Add some sauce on top of the cheese.
Add a meatball, then a little more sauce, and then the cheese. If you are using provolone slices, you would now add two more quarters of cheese per sandwich.
Put the top of the rolls on top of the sandwich and make your garlic butter by combining the butter and the garlic powder in a microwable bowl. Heat for 20 seconds or until it is completely melted.
Brush the butter on top of the rolls, add grated parmesan over the butter, and cover the rolls in tin foil. Bake for 30 minutes.
remove from oven, remove the tin foil and cook for another 5 minutes.
Serve with marinara sauce for dipping! Enjoy!