Cook brown rice if you haven't already.

Cut bell peppers in half, remove seeds and discard. Set aside.

In a large nonstick pan, brown ground turkey with chopped onions and garlic. Use a spatula to break ground turkey into small pieces while it cooks. It should be fully cooked after 7-8 minutes. Remove from heat and add rice, 1 cup tomato sauce (save remaining 1/3 cup for later), Italian seasoning, salt, pepper and cinnamon to the pan. Mix well.

Preheat oven to 375°F. Add halved bell peppers to a 9x13 baking dish. If the peppers are leaning too much, you can trim the bottom of the pepper to help it lay flat in the pan without the stuffing falling out. 

Stuff each bell pepper with about 1/2 cup of the turkey and rice mixture and top each with 1 Tablespoon tomato sauce and a sprinkle of shredded cheese. Carefully pour 1 cup water in between peppers in the bottom of the pan to help steam the peppers while baking.

Cover baking dish with foil and bake for 35 minutes. Remove foil and place peppers back in the oven uncovered for about 5 minutes more, until cheese melts and peppers are soft. Serve immediately.