Preheat your oven to 350°F (175°C).

Bring a large pot of salted water to a boil and cook the egg noodles for 6–8 minutes until al dente.

In a large skillet, heat olive oil over medium heat. Add the ground beef, diced onion, and minced garlic, and sauté for 6–8 minutes until browned.

Stir in Italian seasoning, salt, pepper, and diced tomatoes, and cook for another 2–3 minutes.

In a medium bowl, combine the cream of mushroom soup and sour cream, whisking until smooth.

Grease a 9x13-inch baking dish. Layer half of the cooked egg noodles, half of the beef mixture, and half of the creamy mixture. Repeat layers.

Sprinkle shredded Parmesan cheese over the top of the layered casserole.

Cover with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10–15 minutes until cheese is melted and bubbly.

Let the casserole rest for 5–10 minutes before serving, and garnish with freshly chopped parsley.