Preheat your oven to 375°F (190°C).
Cut the tops off the bell peppers and remove the seeds and membranes. Place them upright in a baking dish.
In a skillet over medium heat, cook the diced onion and minced garlic until softened (about 3-4 minutes).
Add the ground beef (or turkey/vegetable) to the skillet and cook until browned, breaking it up with a spoon (about 5-7 minutes). Drain any excess fat if necessary.
Stir in the cooked rice, diced tomatoes (with their juice), paprika, Italian seasoning, salt, and pepper. Mix well and let it cook for another 2-3 minutes to warm through.
Remove the skillet from heat and stir in half of the shredded cheese.
Spoon the meat and rice mixture into each bell pepper, packing it down gently.
Sprinkle the remaining cheese on top of each stuffed pepper.
Cover the baking dish with foil and bake for 25 minutes. Then, remove the foil and bake for an additional 5-10 minutes until the peppers are tender and the cheese is bubbly and golden.
Remove from the oven, let cool slightly, and garnish with fresh parsley if desired.