In a large skillet, melt 2 tablespoons of butter over medium heat. Add 1 pound of ground beef and cook until browned, about 5-7 minutes. Use a wooden spoon to break up the meat as it cooks, ensuring it's no longer pink. Once cooked, drain excess fat and return the beef to the skillet.

Stir in 1 teaspoon of onion powder, 1 teaspoon of garlic powder, and salt and pepper to taste, mixing well to coat the beef. Cook for an additional 2 minutes.

In a large mixing bowl, combine the seasoned ground beef with 3 cups of cooked white rice, one can of condensed French onion soup, and 1 cup of sour cream. Mix thoroughly until everything is evenly blended.

Preheat your oven to 350°F (175°C) while you prepare the baking dish. Grease a 9x13-inch baking dish.

Spread the beef and rice mixture evenly in the prepared baking dish. Sprinkle 2 cups of shredded mozzarella cheese generously over the top.

Place the baking dish in the preheated oven and bake uncovered for 25-30 minutes until the cheese is bubbly and golden brown.

Once out of the oven, let the casserole cool for about 5 minutes. Sprinkle with chopped parsley before serving.