1. Preheat oven to 375°F (190°C). Wash the bell peppers, slice off the tops, and remove the seeds. If necessary, trim the bottoms to help them stand upright. Microwave or blanch them briefly to soften.

2. In a large skillet, heat olive oil over medium heat. Sauté the chopped onion until soft, about 3-4 minutes. Add garlic and cook another 30 seconds.

3. Add ground beef to the skillet and cook until browned, breaking up the meat. Drain the fat.

4. Stir in cooked rice, drained diced tomatoes, tomato sauce, Italian seasoning, smoked paprika, red pepper flakes (if using), salt, and pepper. Simmer for 5-6 minutes. Remove from heat and mix in 1 cup of shredded cheese.

5. Stuff each bell pepper with the beef mixture and place them upright in a 9×13 baking dish. Spoon a bit of extra tomato sauce on top if desired.

6. Cover with foil and bake for 30 minutes. Remove foil, top with remaining cheese, and bake uncovered for 10-15 more minutes until cheese is melted and bubbly.

7. Remove from oven, let cool slightly, garnish with parsley, and serve warm.