Preheat your oven to 350°F (175°C). Lightly grease a 9×13-inch baking dish and set aside.

Heat the olive oil in a large skillet over medium heat. Add the sliced onions and cook for 10–12 minutes, stirring occasionally, until soft, golden, and caramelized.

Add the ground beef to the skillet with the onions. Break it up with a spatula and cook for 5–7 minutes, until browned and fully cooked. Drain excess fat if needed.

Stir in the garlic powder, Worcestershire sauce, salt, and pepper. Mix well to evenly season the beef and onions.

Meanwhile, cook the egg noodles according to package directions until al dente. Drain and set aside.

In a large bowl, mix together the cooked noodles, beef and onion mixture, French onion soup, and beef broth until well combined.

Transfer the mixture to the prepared baking dish and spread evenly. Sprinkle the shredded Swiss cheese over the top.

Bake for 25–30 minutes, or until the cheese is melted, bubbly, and lightly golden.

Let the casserole rest for a few minutes before serving. Garnish with fresh parsley, if desired.