Creating Easy French Onion Beef Casserole can be a breeze by following these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Cook Beef: In a large skillet, heat olive oil over medium heat. Add the ground beef and cook until browned. Drain excess fat.
3. Sauté Onions: In the same skillet, add the sliced onions. Sauté until they are soft and caramelized, about 10 minutes.
4. Combine Ingredients: In a large bowl, combine the cooked beef, sautéed onions, beef broth, French onion soup mix, cooked egg noodles, and sour cream. Mix well.
5. Layer in Casserole: Pour the mixture into a 9×13 inch baking dish. Spread it evenly.
6. Add Cheese: Sprinkle the shredded Swiss cheese evenly over the top of the casserole.
7. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbly and golden brown.
8. Garnish: Remove from the oven and sprinkle with fresh parsley if desired.
9. Cool: Let it sit for about 5 minutes before serving to allow the casserole to set.

These steps will guide you through making this incredible casserole, ensuring a delicious outcome every time.