Preheat the oven to 350 F. Lightly grease a 9x13-inch baking dish non-stick cooking spray.
Warm the fully cooked Italian meatballs in microwave or oven, as directed.
Using a serrated bread knife, cut the rolls along the equator and place the bottom part into the baking dish.
Place the warmed meatballs onto each slider bun. Spoon the marinara sauce over the top of the meatballs, then sprinkle the grated Parmesan cheese on top of the marinara. Top with the sliced cheese, then the top section of the buns - lining them up so each slider can be cut after it's baked.
Melt the butter and mix in the minced garlic and Italian seasoning combo. Spoon and spread directly on top of the buns.
Bake in the preheated oven for 15-20 minutes, or until cheese has melted and buns begin to golden.
Serve Italian Meatball Slider Bake with fresh fruit or veggies.