01 - Preheat the oven to 375°F. Lightly grease a 9x13 inch baking dish with cooking spray or butter.
02 - In a large skillet over medium-high heat, cook the ground beef until fully browned, breaking it apart into crumbles as it cooks. Drain any excess fat if necessary.
03 - Add the chopped onion, diced bell pepper, and minced garlic to the skillet with the beef. Sauté for 3 to 4 minutes until the vegetables are softened and fragrant.
04 - Stir in the uncooked rice, frozen corn if using, paprika, dried oregano, black pepper, and salt. Cook for 1 minute, allowing the seasonings to bloom and coat the grains evenly.
05 - Pour in the diced tomatoes with their juice and the beef broth. Stir thoroughly to combine all ingredients and bring the mixture to a gentle simmer.
06 - Remove the skillet from heat. Stir in 1 cup of the shredded cheddar cheese and the sour cream until evenly distributed throughout the mixture.
07 - Transfer the entire mixture into the prepared baking dish, spreading it out evenly. Sprinkle the remaining 1 cup of shredded cheddar cheese uniformly across the top.
08 - Cover the baking dish tightly with aluminum foil and bake for 25 minutes to allow the rice to absorb the liquid and cook through.
09 - Remove the foil and continue baking for an additional 15 minutes, until the cheese topping is bubbly, golden, and the rice is fully tender.
10 - Remove the casserole from the oven and let it stand for 5 minutes before serving to allow the layers to set and the flavors to meld.