Place the chicken in a heavy plastic bag set into a large bowl.In a small bowl, stir together olive oil, garlic, salt and ground black pepper. Pour over the chicken breast halves in the heavy plastic bag. Close the bag and turn chicken breast halves to coat well. Marinate in the refrigerator for at least 4 hours or up to 8 hours, turning the bag occasionally. Drain chicken; discard marinade. To broil, place chicken on unheated rack of a broiler pan. Broil 4 to 5 inches from heat for 12 to 15 minutes or until chicken is no longer pink, turning chicken over after half of the broiling time. Or, to grill, place chicken on the rack of an uncovered grill, boned sides up, directly over medium coals. Grill, uncovered, for 12 to 15 minutes or until no longer pink, rearranging the chicken breasts once on each side to produce diamond markings and turning chicken over after half of the grilling time. Transfer chicken to 4 warm serving plates and cut into slices, if you like. Spoon Orange Dijon Glaze on top and sprinkle with some coarsely ground pepper. Garnish with the orange peel and, if you like, the fresh herb sprigs.
Orange Dijon Glaze: In a small saucpean, stir together 1/4 cup thawed frozen orange juice concentrate, 2 to 4 tablespoons Dijon style mustard, 2 tablespoons water, 1 tablespoon balsmic vinegar, if you like, 1 tablespoon olive oil, 1 teaspoon snipped fresh basil, 1 teaspoon snipped fresh mint and 1/2 teaspoon snipped fresh rosemary. Heat until glaze is warmed through. Makes 3/4 cup.