Preheat oven to 450 degrees F.
In a small bowl, whisk together the vinegar, mustard, garlic, sugar and paprika. Set aside.
In a heavy cast iron skillet over medium heat, add the bacon and cook each side until crisp.
Drain the bacon on a napkin lined plate and drain off all but 1 tablespoon of the grease.
Chop the bacon and set aside.
Turn the heat to medium high and add the chicken seasoned with salt and pepper on the skin side), skin side down, season the other side with salt and pepper
Turn down to medium-low heat and cook for 3-5 minutes or until the skin is golden brown, flip and continue cooking another 5 minutes. Remove the chicken to a plate.
Increase the heat to medium and add the butter to the pan.
Once melted, add the onions to cook for 2-3 minutes and then add the potatoes, cooking for 3-4 minutes.
Nestle the chicken and any juices back into the skillet, add the vinegar mixture and the broth, simmer for 1 minute and place in a 450 degree F oven for 35-40 minutes. The juices will thicken up and the chicken will stay moist due to the liquid.
Remove from the oven and sprinkle with chopped bacon and parsley.
Serve spooning the pan juices over the meat and potatoes.
