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