Preheat the oven to 375°F (190°C).
Cut the tops off the peppers and remove the seeds and white membranes. Blanch the peppers in boiling salted water for 3 to 4 minutes. Drain well.
Heat olive oil in a large skillet. Cook the onion for 3 to 4 minutes, then add the garlic and cook for 30 seconds.
Add the ground beef and cook for 5 to 7 minutes, breaking it apart as it browns. Drain excess grease if needed.
Stir in the Italian seasoning, smoked paprika, salt, pepper, and diced tomatoes. Simmer for 3 minutes.
Remove from the heat and stir in the cooked rice and 1 cup of cheddar cheese.
Combine the tomato sauce and beef broth in a 9x13-inch baking dish. Arrange the peppers upright in the sauce.
Fill each pepper with the beef and rice mixture. Cover tightly with foil.
Bake for 30 minutes. Remove the foil and top with the remaining ½ cup cheddar cheese.
Bake uncovered for another 10 to 15 minutes, until the cheese is melted and the peppers are tender. Serve warm.