Grilled Chicken with Balsamic Vinegar (Kristy Anson)

6-8 boneless, skinless chicken breasts
Marinade:
2/3 cup balsamic vinegar
1/4 cup Dijon mustard
1/4 cup olive oil
1 T dried parsley
1 T dried shallots (or 2 T minced fresh shallots)
1 tsp. dried thyme
1/2 tsp. coarse ground black pepper
1 T Spike seasoning
1 tsp. garlic powder
Trim all fat and tendons from chicken breasts and trim underneath side if needed so chicken pieces are all the same thickness. I like to make small slits crosswise along each chicken breast to help the marinade penetrate.Place chicken in zip loc bag, laying them flat. Mix marinade ingredients and pour over chicken. Marinate in refrigerator 4-6 hours or more.Preheat gas or charcoal grill to medium-high. Grill chicken on top side first, rotating a quarter turn after 4-5 minutes if you're wanting those criss-cross grill marks. Use a spray bottle of water if flames shoot up from the oil in the marinade when you first put chicken on the grill. Cook until chicken is well browned on both sides and firm, but not hard to the touch, probably not over 15-20 minutes total cooking time. (Actual cooking time will vary depending on chicken temperature and how hot your grill is, so remove it from the heat when the chicken feels firm when pressed with your finger.) Serve with Arugula and Gorgonzola Salad with Balsamic Vinegar.