Preheat oven to 375°F (190°C). Lightly grease a baking dish.
Slice the tops off the bell peppers and remove seeds and membranes. Arrange peppers upright in the baking dish.
Heat olive oil in a large skillet over medium heat. Sauté onion and garlic until softened.
Add ground beef or turkey to the skillet. Cook until browned and crumbled. Drain excess fat if needed.
Stir in cooked rice, diced tomatoes, tomato paste, Italian herbs, salt, and pepper. Remove from heat and mix in half the shredded cheese.
Fill each bell pepper with the meat and rice mixture. Sprinkle remaining cheese over the tops.
Add a splash of water to the bottom of the baking dish. Cover loosely with foil and bake for 30 minutes.
Uncover and bake for another 10-15 minutes, or until peppers are tender and cheese is golden.
Garnish with fresh parsley before serving if desired.