Prep the oven and pan: Preheat the oven to 375°F (190°C).
Lightly oil a 9x13-inch baking dish or similar casserole pan.
Prepare the peppers: Slice off the tops about 1/2 inch down. Remove seeds and membranes. If a pepper wobbles, trim a thin slice off the bottom to help it stand.
Rub the outsides with a little olive oil and set the peppers upright in the baking dish.
Par-cook the peppers: Add 1/3 cup water to the baking dish, cover tightly with foil, and bake for 12–15 minutes. This softens the peppers so they bake evenly later. Drain any remaining water.
Keep the oven at 375°F.
Sauté the aromatics: While the peppers par-bake, heat 2 tablespoons olive oil in a large skillet over medium. Add the onion with a pinch of salt and cook until translucent, 4–5 minutes. Stir in garlic and cook 30 seconds, until fragrant.
Brown the turkey: Add the ground turkey, breaking it into crumbles.
Season with salt, pepper, Italian seasoning, smoked paprika, and cumin if using. Cook until no longer pink, 5–7 minutes.
Build the sauce: Stir in tomato paste and cook 1 minute to caramelize slightly. Add tomato sauce and chicken broth.
Simmer for 3–4 minutes, stirring, until slightly thickened but still saucy.
Add the rice and cheese: Stir in the cooked rice. If the mixture looks dry, splash in a bit more broth. Off the heat, fold in 3/4 to 1 cup of the shredded cheese.
Taste and adjust seasoning with more salt, pepper, or red pepper flakes.
Stuff the peppers: Spoon the turkey mixture into each pepper, packing it gently and mounding the tops. Sprinkle the remaining cheese over each stuffed pepper.
Bake: Cover the dish loosely with foil and bake 15 minutes. Remove foil and bake another 10–12 minutes, until the peppers are tender and the cheese is melted and lightly browned.
Finish and serve: Let the peppers rest 5 minutes.
Garnish with chopped parsley or cilantro. Serve warm with a simple green salad or roasted vegetables.