Make the Sauce: Cook garlic, onions, and seasonings. Add tomatoes and simmer until thickened.
Prepare Meatballs: Mix ingredients, shape into meatballs, and top with bacon slices.
Cook Meatballs: Grill meatballs at 375°F until fully cooked (165°F internal temperature).
Assemble Sliders: Layer buns with cheese, meatballs, sauce, and more cheese. Add the top bun, brush with butter, and sprinkle seasoning.
Finish on the Grill: Cover sliders with foil and grill for 15 minutes to melt the cheese and toast the buns.
Remove from the grill, rest briefly, and enjoy!