Season the chicken with salt, to taste then sprinkle with cinnamon on all sides so that the thighs are evenly coated.

Heat a cast iron pan over medium high heat. Add a bit of avocado oil, if needed and then add the chicken thighs, skin side down. Cook without moving them for 10-14 minutes, or until the skin has turned crisp and golden and released from the pan. Remove the thighs to a plate, leaving any released oil in the pan and setting the thighs skin side up. Set aside.

To the now empty pan, add the red onions and cook until soft and translucent, about 5 minutes. Add the garlic and tomato paste and cook until fragrant, about two minutes more. Add the wine and reduce until little to no liquid remains. Add the chicken stock, gelatin, soy sauce, tomatoes, and half the oregano. Stir to combine evenly and bring to a simmer.

Add back the chicken thighs, being careful to keep the crisped skin away from any liquid (or else the skin will soften). Nestle the thighs into the liquid until most of the meat is submerged, again making sure the skin is not touching liquid. Simmer for 40 minutes, or until the meat is tender and the liquid is reduced to a thick sauce.

Off heat, add remaining oregano and mint. Serve with feta, if desired.