01 - Preheat your oven to 375°F (190°C). Prepare the bell peppers by carefully slicing off their tops and removing the seeds and membranes. Arrange the hollowed peppers in an upright position within a lightly greased baking dish.
02 - Heat the olive oil in a large skillet over medium heat. Add the finely chopped yellow onion and sauté for 2-3 minutes until it begins to soften.
03 - Incorporate the minced garlic into the skillet and cook for approximately 30 seconds until fragrant. Add the ground turkey, breaking it apart with a spoon, and cook until thoroughly browned, about 5-7 minutes.
04 - Stir in the diced tomato, cooked rice or quinoa (if using), dried oregano, dried basil, smoked paprika, salt, and black pepper. Continue to cook for another 2-3 minutes, ensuring the mixture is well combined and heated through.
05 - Remove the skillet from the heat. Stir in 1/2 cup of the shredded mozzarella cheese and 1/4 cup of the grated Parmesan cheese until just combined.
06 - Evenly spoon the prepared turkey mixture into each of the bell peppers. Top each stuffed pepper with the remaining shredded mozzarella and grated Parmesan cheese.
07 - Cover the baking dish tightly with aluminum foil. Bake for 30 minutes. Remove the foil and continue baking for an additional 10 minutes, or until the cheese is golden brown and the peppers are tender.
08 - Allow the stuffed peppers to rest for 5 minutes before serving to allow the flavors to meld.