Prepare a medium-high (400°F to 475°F) gas or
charcoal grill fire.
Place each chicken breast between two sheets of
parchment paper and pound with a kitchen mallet
to a uniform thickness. Brush both sides of the
chicken with the vegetable oil, and season
generously with salt and pepper. grill, turning
once, until cooked through (165°F), 6 to 10
minutes. Transfer to a cutting board, tent with
foil, and let rest 5 minutes.
Meanwhile, in a small bowl, combine the
vinegar, shallot, mustard, and sugar. Whisk in
the olive oil; stir in the olives and parsley.
Thickly slice the chicken and serve with the
vinaigrette spooned over it.
