Begin by whisking together the ketchup, apple cider vinegar, packed brown sugar, molasses, Worcestershire sauce, ground mustard, garlic powder, onion powder, black pepper, and ¼ cup water. Set aside 1/3 cup of this mixture for later use.

Place the chicken breasts in a large bowl or a gallon-sized slider bag, then pour the remaining ketchup mixture over them. Seal the bag or cover the bowl and marinate in the refrigerator for at least 1 hour, preferably overnight, occasionally turning the bag to ensure even marination. After marinating, drain the chicken and discard the marinade.

Preheat your grill to medium-high heat.

Using a grilling fork, poke drainage holes into a sheet of Reynolds Wrap® Non-Stick Foil. Position the foil sheet on the grill grate with the non-stick (dull) side facing up.

Arrange the chicken breasts on the foil and grill them, turning once and brushing with the reserved 1/3 cup marinade, until thoroughly cooked. This should take approximately 10-12 minutes per side.

Serve the grilled chicken immediately, garnished with chopped fresh parsley if desired.