Place chops between 2 sheets of waxed paper. With meat mallet, rolling pin or the flat bottom of a heavy skillet, flatten the chops slightly. Season on both sides with salt and pepper.
Whisk together the barbecue sauce, pineapple juice, soy sauce and oil in a 9-inch glass pie plate. Add the meat, turning to coat with the marinade. Cover with plastic wrap; refrigerate for 1 hour, turning pork over after 30 minutes.
Prepare outdoor grill with medium-hot coals or heat the broiler.
Remove the chops from the marinade. Transfer the marinade to a small saucepan. Boil the marinade for 1 minute. Remove the saucepan from the heat; swirl in the butter until just incorporated, but not fully melted. Reserve the sauce.
Grill or broil pork chops for about 8 minutes, turning the chops over once. Transfer the meat to a platter. Spoon the sauce over the chops. Sprinkle with the chopped parsley. Serve immediately. Makes 4 servings.