Heat a large oven-safe skillet over medium-high heat. Add the ground beef and cook, breaking it up with a wooden spoon, until it starts to brown, about 5 minutes. Add the diced onion and continue cooking until the beef is fully browned and the onion is soft, about 4 more minutes. Stir in the garlic and cook for 30 seconds until fragrant. Drain excess fat if needed.

Stir in the rinsed rice, beef broth, drained tomatoes, Worcestershire sauce, smoked paprika, salt, and pepper. Bring to a boil, then reduce heat to low, cover tightly, and simmer for 18 minutes until the rice is tender and most of the liquid is absorbed. Remove from heat and let stand, covered, for 5 minutes.

Preheat your oven to 375°F. Fluff the rice mixture with a fork. Stir in half the shredded cheddar and all the sour cream until evenly combined. The mixture should look creamy but not soupy.

Smooth the top and sprinkle with the remaining cheddar. Bake uncovered for 15-20 minutes until the cheese is fully melted and starting to brown at the edges. Let rest for 5 minutes before serving - it will be very hot.