You can broil the chicken and make the sauce a day ahead. Refrigerate the sauce and chicken separately, or toss the chicken with the sauce and refrigerate them together for an even deeper lemony flavor. Let the chicken come to room temperature about twenty minutes before broiling it with the sauce. This last five minute broil won't heat the chicken all the way through, just warm it up on the outside. Leftovers are also fantastic cold or at room temperature. The parsley is optional only because if you happen to have one of those kids who runs screaming from the table if anything has a fleck of green in it, you will not want to inflict the horrors of parsley upon your little prince or princess.