Ingredients

• 2 tablespoons olive oil
• 6 ounces pancetta, diced
• 1 yellow onion, finely chopped
• 2 garlic cloves, minced
• Pinch crushed red pepper flakes
• 1 (14-ounce) can crushed tomatoes
• 1/2 teaspoon kosher salt, plus more for seasoning
• 1/2 teaspoon freshly ground black pepper, plus more for seasoning
• 1/2 cup grated Pecorino Romano
• 1 small (6-ounce) onion, grated
• 1/2 cup chopped fresh flat-leaf parsley, plus 1/4 cup
• 2/3 cup grated Parmesan cheese, plus 1/4 cup
• 1/3 cup Italian-style bread crumbs
• 1 large egg
• 2 tablespoons ketchup
• 3 garlic cloves, minced
• 1/4 teaspoon crushed red pepper flakes
• 1 teaspoon kosher salt, plus more for seasoning
• 1/2 teaspoon freshly ground black pepper, plus more for seasoning
• 8 ounces ground beef
• 8 ounces ground veal
• 2 ounces smoked mozzarella cheese, cut into 16 (1/2-inch) cubes
• 1 pound bucatini or other long pasta

Instructions

1. Watch how to make this recipe.
2. For the sauce: In a large heavy skillet, heat the oil over medium heat. Add the pancetta and cook, stirring constantly, until golden brown, about 5 to 7 minutes. Using a slotted spoon, remove the pancetta and reserve. Add the onion and cook for 5 minutes. Stir in the garlic and red pepper flakes and cook until fragrant, about 30 seconds. Add the tomatoes, 1/2 teaspoon salt, 1/2 teaspoon black pepper, and the cooked pancetta. Simmer, uncovered, over medium-low heat until the sauce thickens, about 15 minutes. Stir in the cheese and season with salt and pepper, to taste.
3. For the meatballs: Position an oven rack in the lower 1/3 of the oven. Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper.
4. In a large bowl, combine the onion, 1/2 cup parsley, 2/3 cup Parmesan, bread crumbs, egg, ketchup, garlic, red pepper flakes, 1 teaspoon salt, and 1/2 teaspoon pepper. Add the beef and veal. Using your hands, combine all ingredients gently but thoroughly. Shape the meat mixture into 16 (1 1/2-inch-diameter) meatballs and place on the prepared baking sheet. Make a hole in the center of each meatball and place a cube of mozzarella inside. Reform the meatball so that the mozzarella is completely covered with the meat mixture. Bake the meatballs for 15 minutes until cooked through.
5. Bring a large pot of salted water to a boil over high heat. Add the pasta and cook until tender but still firm to the bite, stirring occasionally, about 8 to 10 minutes. Drain and place in a large serving bowl. Add the meatballs and sauce. Toss gently and season with salt and pepper, to taste. Sprinkle with the remaining parsley and Parmesan.