Cook the egg noodles according to the package directions.
Rinse and drain the noodles well, then set them aside.
In a large skillet, heat the olive oil over medium heat.
Add the lean ground beef, diced onion, and minced garlic to the skillet.
Cook until the ground beef is fully browned and the onion is softened.
Drain any excess grease, if necessary.
Sprinkle the beef mixture with Italian seasoning.
Add the tomato sauce to the skillet.
Season with salt and black pepper to taste.
Stir until the beef mixture is evenly coated with the sauce.
Add the cooked egg noodles to the beef mixture.
Stir until the noodles and beef mixture are fully combined.
Lightly grease a casserole dish.
Transfer the beef and noodle mixture into the prepared casserole dish.
Spread the mixture evenly.
Preheat the oven to 400°F.
Sprinkle the shredded cheddar cheese evenly over the top of the casserole.
Bake for 15 minutes, or until the cheese is completely melted and the casserole is heated through.
Remove the casserole from the oven.
Sprinkle with freshly chopped parsley before serving.
Serve warm.