Preheat your oven to 375°F. Prepare a 9x13-inch baking dish by spreading about 1/3 cup of crushed tomatoes or sauce across the bottom to keep the peppers moist while baking.
Trim the tops off the bell peppers and remove seeds and membranes. If needed, level the bottoms so each pepper stands upright. Place peppers cut-side up in the prepared baking dish.
Heat the olive oil in a large skillet over medium-high heat. Add the chopped onion and cook, stirring occasionally, until softened, about 4 minutes. Add the garlic and cook 30 seconds until fragrant.
Add the ground turkey to the skillet, breaking it up with a spoon. Cook until no longer pink, about 6–8 minutes. Season with salt, pepper, Italian seasoning and smoked paprika while it browns.
Stir in the crushed tomatoes and drained diced tomatoes, reduce heat to medium, and simmer uncovered 6–8 minutes to thicken slightly. Taste and adjust seasoning.
Remove the skillet from heat and fold in the cooked rice and half of the shredded cheese until evenly combined. Let the filling sit 2–3 minutes so flavors meld and mixture is easy to scoop.
Spoon the turkey mixture into each prepared pepper, pressing gently to fill. Pack the filling slightly above the rim so each pepper is generously stuffed. Sprinkle the remaining cheese over the tops.
Cover the dish tightly with foil and bake at 375°F for 30 minutes. Remove the foil and bake an additional 8–10 minutes until peppers are tender and cheese is melted and starting to brown. For extra color, place under the broiler 1–2 minutes — watch closely.
Let the peppers rest 5 minutes before serving. Garnish with chopped parsley and serve with any pan juices spooned over the top.