01 - Preheat the oven to 375°F. Lightly grease a 9x13 inch baking dish with nonstick spray or butter.
02 - In a large skillet over medium-high heat, cook the ground beef until fully browned, breaking it apart with a spoon as it cooks. Drain excess fat if needed.
03 - Add the chopped onion, bell pepper, and minced garlic to the skillet. Sauté for 3 to 4 minutes until the vegetables are softened and fragrant.
04 - Stir in the uncooked rice, frozen corn if using, paprika, oregano, black pepper, and salt. Cook for 1 minute to toast the rice and bloom the spices.
05 - Pour in the diced tomatoes with their juice and the beef broth. Stir well 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 mixture into the prepared baking dish, spreading it into an even layer. Sprinkle the remaining 1 cup of shredded cheese evenly over the top.
08 - Cover the 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 is bubbly and golden and the rice is fully tender.
10 - Remove from the oven and let the casserole stand for 5 minutes to set before scooping and serving.