In a large skillet over medium heat, brown the ground beef, breaking it up with a spatula until no longer pink, about 7-10 minutes. Drain excess grease and set aside.

In the same skillet, heat a tablespoon of oil or butter. Add the chopped onion and sauté until soft and golden, about 5-7 minutes.

In a mixing bowl, combine the cooked beef, sautéed onions, rice, French onion soup, garlic powder, salt, and pepper. Mix thoroughly.

Transfer the mixture into a greased 9x13 inch casserole dish, spread evenly, and top with shredded cheese.

Cover with foil and bake at 350°F (175°C) for 30 minutes. Remove foil and bake for an additional 10-15 minutes until cheese is melted and golden.

Let the casserole sit for 5-10 minutes before serving to allow it to set. Scoop onto plates and enjoy!