Preheat oven to 350.
In a large pot over medium heat cook meatballs, marinara sauce and Italian seasoning. Stir occasionally. Once meatballs are fully cooked cover and simmer for 10-15 minutes.
Use a nonstick spray to coat the bottom of two 9 x 13 baking pans. Cut buns in half and place with cut side up, covering the entire pan. 24 buns should fit in each pan.
Cut meatballs in half. Place one meatball half on each bun and use sauce to cover all buns evenly. Spread provolone slices on the meatballs and sauce. Place bun tops on top of the cheese.
Use a brush to spread melted butter over the top of all the buns. Evenly spread parmesan cheese on top.
Cover pans with foil and bake for 15 minutes. Remove foil and cook 3-5 more minutes. Use a spatula to separate and remove sliders from pan. Serve warm.