Combine the marinade ingredients in a small bowl or glass measuring cup and whisk well.
This will make 1 ½ cups, or 12 ounces. Reserve ½ cup for salad dressing if you are making a salad.
Butterfly the chicken breast pieces in half horizontally or pound thin with a meat mallet.
Cover with 1 cup of marinade and let sit in fridge for at least 1 hour or up to 24 hours.
Preheat grill to medium heat or 400°F (20°C).
Place chicken on hot grill grates and brush some of the leftover chicken marinade onto the chicken. Optional, but adds a boost of flavor!
Grill chicken breast on first side for 3 minutes, then flip and continue cooking for 4-5 minutes or until chicken breast reaches 165°F (74°C) internal temperature. Let rest for at least 5 minutes before slicing.