Preheat the oven to 350°F (175°C).
In a large skillet over medium-high heat, brown the ground beef until fully cooked and no pink remains. Drain excess fat thoroughly.
In a 9x13 inch baking dish, combine the browned beef, uncooked white rice, condensed French onion soup, beef consomme, water, melted butter, and black pepper. Stir until the ingredients are evenly distributed.
Cover the baking dish tightly with aluminum foil to ensure steam is trapped for the rice to hydrate.
Place the dish in the oven and bake for 30 minutes.
Remove the foil and sprinkle the shredded Gruyere cheese and crispy fried onions evenly over the surface.
Return the dish to the oven, uncovered, and bake for an additional 15 minutes until the rice is tender and the onion topping is golden brown.
Remove from the oven and allow the casserole to rest for 5 to 10 minutes before serving to allow the sauce to thicken.