Bring a large pot of salted water to a boil. Add macaroni and cook until just al dente (slightly firm). Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add ground beef and cook until no longer pink, breaking it apart with a spoon. Drain excess fat if needed.

Stir in onion and garlic; cook for 2-3 minutes until softened. Add tomato sauce, diced tomatoes, Italian seasoning, salt, and pepper. Let simmer for 5-7 minutes to blend flavors.

Add the drained macaroni into the beef mixture and stir well to coat.

Preheat oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish. Spread half of the beef-pasta mixture in the dish, sprinkle with half the cheddar cheese. Add the remaining mixture, then top with mozzarella and the rest of the cheddar.

Place uncovered in the oven and bake for 20-25 minutes, or until cheese is melted and bubbling.

Garnish with parsley if desired and serve warm.