Preheat the oven to 350° F. Lightly spray a casserole dish with nonstick cooking spray.

Heat the olive oil in a medium skillet over medium heat. Add diced onion, carrots, and garlic. Season with salt and pepper, to taste. Cook, stirring occasionally, until the vegetables become translucent, approximately 3-4 minutes.

Add passata and let the sauce simmer for 6-8 minutes.

Meanwhile, bring a large pot of salted water to a boil. Add pasta and cook al dente, 2-3 minutes less than the package instructions.

Drain the pasta and return to the cooking pot. Add one-third of the tomato sauce to the pasta and stir to evenly coat pasta. Transfer the pasta to the prepared casserole dish.

In a medium bowl, combine the ground beef, grated onion, breadcrumbs, parmesan, egg, oregano, basil, and one-half of the fresh parsley.

Generously season with salt and pepper and begin working the mixture with your hands. Mix just until everything is combined, but don’t overwork the meatball mixture. Roll into 14-16 meatballs and place the meatballs on top of the pasta layer.

Pour the remaining tomato sauce over the meatballs. Sprinkle with the shredded mozzarella cheese.

Cover the casserole with aluminum foil and place in the oven to bake for 25 minutes. Remove foil and bake for another 15 minutes, just until the cheese has melted and is golden-brown.

Serve garnished with the remaining fresh parsley. Enjoy!