Prep the peppers: Preheat your oven to 375°F (190°C).
Slice the tops off the bell peppers, remove seeds and membranes, and trim the bottoms just enough so they stand upright (don’t cut a hole). Lightly salt the insides.
Soften the peppers (optional but helpful): Place peppers cut-side up in a baking dish with 1/4 cup water, cover tightly with foil, and bake for 10 minutes. This gives you tender peppers without overcooking later.
Drain any water after par-baking.
Sauté the aromatics: In a large skillet, heat olive oil over medium. Add onion and a pinch of salt. Cook 4–5 minutes until translucent.
Stir in garlic and cook 30 seconds until fragrant.
Brown the turkey: Add ground turkey, salt, pepper, smoked paprika, oregano, cumin, and red pepper flakes if using. Cook, breaking it up with a spoon, until no longer pink and lightly browned, about 6–8 minutes.
Make it saucy: Stir in diced tomatoes and tomato sauce. Simmer 3–4 minutes to thicken slightly.
Taste and adjust seasoning with more salt or a pinch of sugar if tomatoes are very sharp.
Fold in greens and grains: Off the heat, mix in cooked brown rice (or quinoa), chopped spinach, 1/2 cup of the cheese, parsley or cilantro, and lemon juice or vinegar. The filling should be moist but not watery. If it seems dry, add a splash more tomato sauce or water.
Stuff the peppers: Coat the baking dish with cooking spray or a little oil.
Spoon the filling into each pepper, gently pressing down to pack. Top with the remaining 1/4 cup cheese.
Bake: Cover the dish with foil and bake 20 minutes. Uncover and bake another 8–10 minutes, until the peppers are tender and the cheese is melted and lightly golden.
Finish and serve: Let rest 5 minutes.
Garnish with extra herbs. Serve with a green salad or a dollop of plain Greek yogurt if you like a creamy contrast.