Preheat your oven to 375 degrees F. Remove the skin from the chicken (it helps to grasp it with a paper towel and tug it off.) Discard the skin.
Place your chicken in a roasting pan or a sheet pan lined with greased foil for easy cleanup. Lightly salt the chicken.
In a medium bowl, whisk the ketchup, vinegar and mustard until blended. Pour all the sauce over the chicken and brush it over the pieces to cover them completely.
Bake, uncovered, for 45 minutes, or until the chicken is no longer pink inside. Then, broil the chicken in the pan on the center rack of the oven for 2 minutes to 2 1/2 minutes to caramelize the sauce a bit. Watch it carefully so it doesn't burn. Store leftovers in the refrigerator for up to four days.
You can easily cut this recipe in half and bake your chicken in a cast iron skillet or stone baking dish. Also, I added dried parsley as garnish for the photos, although it's usually not part of this recipe. It's a nice touch for company, though!