Preheat your oven to 375°F (190°C). Cut the tops off the bell peppers and remove the seeds and membranes. Lightly brush the peppers with olive oil and arrange them upright in a baking dish.

Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the diced onion and garlic, cooking until softened. Stir in the ground beef, breaking it up with a spoon, and cook until browned. Drain any excess fat. Add the tomato paste, diced tomatoes, smoked paprika, Italian seasoning, salt, and pepper. Cook for another 2-3 minutes. Remove the skillet from heat and mix in the cooked rice and half of the shredded cheese.

Fill each bell pepper generously with the ground beef mixture, pressing it down slightly. Sprinkle the remaining cheese over the tops of the stuffed peppers. Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the peppers are tender and the cheese is melted and bubbly.

Remove the stuffed peppers from the oven and let them cool slightly. Garnish with fresh parsley or basil and serve warm, optionally with a dollop of sour cream.