Prepare the peppers: Wash the bell peppers and cut off the tops. Remove the seeds and white membranes from inside each pepper. Arrange the peppers upright in a baking dish.
Cook the beef: Heat a large skillet over medium heat. Add the ground beef and cook while breaking it apart until browned and fully cooked. Drain excess grease if necessary.
Cook the aromatics: Add the diced onion and cook for 3–4 minutes until softened. Add the minced garlic and cook for about 30 seconds until fragrant.
Prepare the filling: Add the diced tomatoes, tomato sauce, cooked rice, Italian seasoning, paprika, black pepper, salt, and chili powder. Stir well and simmer for 3–5 minutes so the flavors combine.
Stuff the peppers: Spoon the beef and rice mixture evenly into the prepared bell peppers. Do not pack the filling too tightly.
Add cheese: Sprinkle the shredded cheese over the top of each stuffed pepper.
Bake: Cover the baking dish with aluminum foil and bake at 375°F (190°C) for 30 minutes.
Finish baking: Remove the foil and bake for another 10–15 minutes, until the peppers are tender and the cheese is melted and lightly golden.
Serve: Remove from the oven and let the peppers rest for a few minutes. Garnish with fresh parsley and serve warm.