Preheat your oven to 350°F (175°C).
In a large skillet over medium heat, cook the ground beef and onions until the beef is browned and the onions are translucent.
Stir in the cream of mushroom soup, milk, garlic powder, paprika, salt, and pepper, combining until smooth.
Add the rice and mix well, allowing the rice to soak up all the flavors.
Sprinkle half of the shredded cheddar cheese into the mixture, reserving the remainder for topping.
Transfer the mixture to a greased 9x13-inch baking dish, spreading it evenly.
Top with the remaining cheddar cheese, spreading it evenly over the surface.
Cover the dish with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 15 minutes until the cheese is bubbly and golden brown.
Remove from the oven and let it sit for 5-10 minutes before serving.