Step 1: Preheat your oven to 375°F (190°C) and lightly grease a 9×13 inch baking dish.
Step 2: In a large skillet or Dutch oven, brown the ground beef over medium-high heat. Break it apart with a spoon as it cooks. Once no longer pink, drain any excess fat.
Step 3: Add the chopped onion and bell pepper to the skillet with the ground beef. Cook for 5-7 minutes, or until the vegetables are softened. Stir in the minced garlic and cook for another minute until fragrant.
Step 4: Stir in the uncooked white rice, beef broth, cream of mushroom soup, tomato paste, Worcestershire sauce, dried oregano, salt, and black pepper. Bring the mixture to a simmer, then reduce heat to low, cover, and cook for 15-20 minutes, or until the rice is nearly tender and most of the liquid has been absorbed. Stir occasionally to prevent sticking.
Step 5: Remove the skillet from the heat. Stir in 1 cup of the shredded cheddar cheese until melted and fully incorporated into the mixture.
Step 6: Transfer the beef and rice mixture to the prepared baking dish, spreading it evenly. Top with the remaining 1 cup of shredded cheddar cheese.
Step 7: Bake for 15-20 minutes, or until the cheese is melted and bubbly and the casserole is heated through. For an extra golden crust, you can broil for the last 1-2 minutes, watching carefully to prevent burning.
Step 8: Remove from oven and let stand for 5 minutes before serving.