1. Remove the bones from the pork chops with a sharp knife. Holding the knife parallel to the surface of the meat, split the chops in half, but do not cut entirely through. Spread the split chops so that they lie fairly flat.
2. In a skillet heat two tablespoons of the butter, add the chops and brown on both sides. Remove the chops. Heat the remaining butter in the pan, add the onion and saute three minutes. Add the flour, salt, mustard and pepper and stir until well blended. Gradually add the heated stock and chopped pickle and simmer five minutes.
3. Return the chops to the skillet and spoon the sauce over them. Cover and simmer until the chops are tender, about fifteen minutes.