Preheat the oven to 375°F (190°C). Lightly grease your 9x13-inch baking dish.

In a large skillet, brown the ground beef over medium heat, draining any excess fat after cooking.

Add the diced onion and minced garlic to the skillet for 2-3 minutes until softened.

Stir in the tomato sauce, diced tomatoes, Italian seasoning, salt, and black pepper. Simmer for about 5 minutes to combine flavors.

Meanwhile, cook the elbow macaroni according to package instructions until al dente. Drain and set aside.

In a large mixing bowl, combine the cooked macaroni, the beef mixture, cheddar cheese, mozzarella cheese, and sour cream. Ensure it is mixed well.

Transfer the mixture to the prepared baking dish, making sure it’s evenly spread. Top with grated Parmesan cheese.

Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the cheese is melted and golden.

Let cool for 5 minutes before serving.