Preheat your oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until softened, about 5 minutes.
Add the ground beef to the skillet. Season with black pepper and garlic powder. Cook until browned, breaking it up with a spoon, about 7-10 minutes. Drain excess fat if necessary.
In a mixing bowl, combine the beef mixture, rice, beef broth, and the French onion soup mix. Stir well to combine.
Transfer the mixture into a greased casserole dish. Spread evenly.
Cover the casserole dish with foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and sprinkle shredded cheddar cheese over the casserole. Bake uncovered for an additional 15 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let it sit for 5-10 minutes. Garnish with fresh parsley if desired before serving.