Preheat the oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the sliced onion and cook until soft and caramelized, about 8-10 minutes, stirring occasionally to prevent burning.
Add the ground beef to the skillet with the onions, season with salt and pepper, and cook until the beef is browned and crumbled, about 5-7 minutes. Drain excess fat if necessary.
In a large mixing bowl, combine the beef mixture, beef broth, uncooked rice, cream of mushroom soup, and the onion soup mix. Stir until well combined.
Pour the mixture into a greased 9x13 inch baking dish and spread evenly.
Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and sprinkle the shredded cheddar cheese on top. Return to the oven uncovered and bake for an additional 15 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for a few minutes. Garnish with fresh parsley if desired.
Serve warm.