Make the sauce:

Place all ingredients in a medium saucepan over medium heat. Bring to a boil, stirring to dissolve the sugar. Reduce the heat to low and simmer until slightly thickened, about 10 minutes. Remove from heat. The sauce will thicken slightly as it cools.

Make the chicken:

Preheat oven to 400°. Season chicken all over with salt and pepper. Heat a 10 inch or larger cast iron or oven safe skillet over medium high heat for 5 minutes. Add the chicken skin side down and cook until the fat is rendered and the skin is crisp and golden-brown., 6 to 8 minutes.

Flip the chicken. Pour about 1/2 of the sauce evenly over the chicken. Place the skillet in the oven and roast for 10 minutes. Remove the pan from the oven and spoon the sauce from the bottom of the skillet over the chicken. Pour the remaining reserved sauce over the top. Return to the oven and roast until internal temperature reaches 165°, about 20 minutes more.