Preheat oven to 350 F.
De-stem and de-seed peppers. Cook whole peppers uncovered in boiling water for about 5 minutes. Remove with tongs, dunk in cold water, and invert to drain well.
Cook onion and olive oil in a skillet over medium heat for 3 minutes. Add ground chicken, breaking it up as it cooks, about 7 minutes. Drain excess fat.
Add remaining ingredients except for cheese, stirring until heated through. Stuff peppers with chicken mixture. Place peppers upright in a casserole dish or roasting pan. (If pepper won’t stand on its own, cut a thin slice off the bottom to make it level.)
Cover with aluminum foil and bake 25 minutes. Remove foil, top peppers with cheese, and bake another 5 minutes or so until cheese has melted and begun to brown slightly.
Note: Look for bell peppers that are of similar size to ensure even cooking time. Peppers with 4 bumps on the bottom sit better than those with 3 bumps.
Per serving: 470 calories, 19 grams fat (8 grams saturated fat), 40 grams total carbohydrates, 6 grams fiber, 35 grams protein.
