FOR THE CHICKEN
The day before serving, brine the chicken for one hour in the brine mixture noted above. Drain and set aside when time is up. (NOTE: THIS STEP IS OPTIONAL)
When ready to grill: Heat grill to medium-high. Place reserved lemon halves on the grill and grill until softened and grill marks appear. Remove chicken from marinade and grill until internal temperature reaches 165 for breasts, and 180 for thighs
FOR THE MARINADE
While chicken is brining, make the marinade. Combine olive oil, Limoncello, lemon juice and garlic. Place chicken in a zip lock bag and pour in marinade. Lay flat in a glass dish and turn every once in awhile to make sure marinade gets a chance to infuse into all of the chicken. You can do this up to 24 hours in advance of grilling.
FOR THE VINAIGRETTE
Remove the zest from the lemons, cut in half and set aside. Combine the zest with the Limoncello and Dijon mustard. SLOWLY drizzle the Extra Virgin Olive Oil into the other ingredients. This is much easier if you happen to have a blender handy, but doing it the old fashioned way with your bare hands works too. You want to give the oil enough time to get to know that mustard and form a thickened emulsion. If you go too fast, they won't get together very well and your vinaigrette either won't be thick and rich, and it might look curdled or broken. Translation = Patience is a big deal here.
Set aside once you've gotten that far.
When your grilled lemons come off the grill, squeeze their juice into the vinaigrette and mix well.
Check for seasonings and add salt and pepper if needed.
When chicken is cooked and comes off the grill, drizzle generously with Vinaigrette before chowing down.