01 - Preheat your oven to 400°F. Grease a 9x13 inch baking dish with cooking spray or olive oil.
02 - In a large mixing bowl, combine ground beef, Italian sausage, breadcrumbs, grated Parmesan, egg, minced garlic, chopped parsley, dried oregano, salt, and black pepper. Mix until just combined—avoid overworking the meat.
03 - Roll the mixture into 1-inch balls, approximately 2 tablespoons each, and place on a rimmed baking sheet or tray.
04 - Heat a large skillet over medium-high heat with a splash of olive oil. Brown meatballs in batches for 5–6 minutes, turning to sear all sides. Remove from heat once browned—interior will finish cooking in the oven.
05 - Bring a large pot of salted water to a boil. Cook pasta until just al dente, 2 minutes less than package instructions. Drain thoroughly in a colander and set aside.
06 - In the same skillet, heat 2 tablespoons olive oil over medium heat. Sauté onion until softened, about 5 minutes. Add garlic and cook 1 minute until fragrant. Stir in crushed tomatoes, tomato paste, dried basil, chili flakes, sugar, salt, and pepper. Simmer for 10 minutes until slightly thickened.
07 - Toss the drained pasta with half the tomato sauce and transfer to the prepared baking dish. Arrange browned meatballs evenly over the pasta, then pour the remaining sauce over the top.
08 - Sprinkle shredded mozzarella and grated Parmesan cheese evenly across the entire surface.
09 - Bake for 25–30 minutes until cheese is golden and sauce is bubbling around the edges. Let rest for 5 minutes before serving to allow the dish to set.
10 - Garnish with fresh basil leaves if desired. Serve warm alongside crusty bread and a green salad.