Preparation:

1. Preheat oven: Preheat oven to 375°F (190°C). Butter a 9 x 13-inch baking dish and set aside.
2. Cook ground beef: In a large skillet, heat olive oil over medium-high heat. Add ground beef and brown, breaking it up with a spoon. Add chopped onion and garlic and cook for 2 to 3 minutes, until onions are soft and translucent. 3. Season beef: Stir in onion soup, beef broth, and uncooked rice. Season to taste, then bring to a simmer. Simmer for 2 to 3 minutes to allow flavors to blend.
4. Assemble gratin: Pour beef and rice mixture into prepared baking dish. Cover with foil and bake for 25 to 30 minutes, or until the rice is tender and the liquid is absorbed.
5. Adding the cheese and final baking: Remove the foil and sprinkle the gratin evenly with grated mozzarella and Parmesan cheese. Return the dish to the oven and bake for another 5 to 7 minutes, until the cheese is melted and bubbly.
6. Serving: Garnish with fresh parsley and serve warm. This hearty gratin is perfect for a comforting dinner!

Baking time: 45 minutes
Servings: 6
Calories: ~500 per serving