How to Make It
Heat broiler. Bring a large pot of water to a boil for the pasta. In a food processor, combine the onion, bacon, garlic, and parsley; pulse until finely chopped, 10 to 15 times. Transfer to a medium bowl, add the beef, Parmesan, bread crumbs, egg, ½ teaspoon salt, and ¼ teaspoon pepper, and mix gently to combine.
Form the beef mixture into 16 meatballs (about 2 tablespoons each) and place on a foil-lined broilerproof rimmed baking sheet. Broil, turning once, until cooked through, 10 to 12 minutes.
Cook the pasta according to the package directions.
Heat the marinara sauce in a large skillet over medium heat, 2 to 3 minutes; add the meatballs and toss gently to coat. Serve over the pasta and sprinkle with the shaved Parmesan.