01 - Set the oven to 375°F (190°C) to warm up.
02 - Cut off the tops of the bell peppers, remove seeds and membranes, then stand them upright in a baking dish.
03 - Heat olive oil in a large skillet over medium heat. Add the chopped onion and cook until softened, approximately 4 minutes.
04 - Add minced garlic to the skillet and cook for 1 minute. Incorporate the ground beef, breaking it apart, and cook until browned and fully cooked, about 6 to 7 minutes.
05 - Stir in diced cherry tomatoes, drained canned tomatoes, cumin, smoked paprika, oregano, salt, and black pepper. Reduce heat and simmer for 5 minutes until most liquid evaporates.
06 - Remove skillet from heat and mix in cooked rice, crumbled feta cheese, chopped parsley, and pine nuts if using.
07 - Spoon the beef and rice mixture evenly into each bell pepper, packing gently.
08 - Optionally replace the pepper tops. Add 2 to 3 tablespoons of water to the bottom of the baking dish.
09 - Cover the dish with foil and bake for 30 minutes.
10 - Remove the foil and continue baking for 15 minutes until the peppers are tender and tops are lightly browned.
11 - Allow the peppers to cool for 5 minutes before serving. Garnish with additional parsley if desired.