Prepare the Bell Peppers:
Preheat your oven to 375°F (190°C). Cut the bell peppers in half lengthwise and remove the seeds and membranes. Place them in a baking dish cut side up.

Cook the Filling:
In a large skillet, heat olive oil over medium heat. Add chopped onion and minced garlic, sauté until the onion is translucent. Add the ground beef or turkey, cooking until browned. Drain any excess fat. Stir in cooked rice, drained tomatoes, oregano, basil, salt, and pepper. Cook the mixture for about 5 minutes until flavors meld together.

Stuff the Peppers:
Spoon the beef and rice mixture into each pepper half. Top with shredded mozzarella cheese.

Bake:
Cover the baking dish with aluminum foil. Bake in the preheated oven for 30 minutes. Remove foil and bake for an additional 10 minutes, or until the peppers are tender and cheese is bubbly and golden.

Garnish and Serve:
Sprinkle with fresh parsley before serving. Serve hot.