Preheat oven to 350*.
Add oil to sauce pan and place over medium/low heat. When warmed, add onion and garlic and let soften.
While onions and garlic are softening, add the rest of the ingredients (except for chicken) to a large bowl and whisk. Add the sauce to the pan and reduce for 30 minutes on the stove top.
While sauce reduces, dry the chicken thoroughly with paper towels. Be sure to dry under the skin as well. Heat 2 tbs canola oil in a heavy bottomed cast iron skillet. Just before it starts to smoke, add chicken skin side down.
Cook until brown and crispy. If the skin sticks, leave it. It will release on it's own when it's properly browned. Flip chicken skin side up and then place in the oven.
Cook for 15 minutes, then remove chicken and brush with sauce. Place back in the oven and cook for 5 minutes. Pull out and reapply sauce. Continue adding more sauce and sticking back in the oven again and again until a thermometer reads 145*.
Pull the chicken out of the oven and let rest. It will rise to the appropriate temperature while resting.