Place the chicken breasts on a cutting board. Cover with plastic wrap and gently pound the thicker areas until the chicken is about 3/4 inch thick.
2 pounds boneless skinless chicken breasts
In a large bowl or gallon-size zip-top bag, whisk together the balsamic vinegar, olive oil, Dijon mustard, honey, garlic powder, Italian seasoning, salt, and black pepper.
¼ cup balsamic vinegar, 3 tablespoons olive oil, 1 tablespoon Dijon mustard, 1 tablespoon honey, 1 teaspoon garlic powder, 1 teaspoon Italian seasoning, 1 teaspoon salt, ½ teaspoon black pepper
Add the chicken breasts and turn to coat well in the marinade. Cover or seal and refrigerate for at least 30 minutes or up to 4 hours.
Remove the chicken from the refrigerator and preheat an outdoor grill to medium-high heat, about 400°F. Clean and lightly oil the grill grates to help prevent sticking.
Remove the chicken from the marinade, letting the excess drip off. Discard the used marinade.
Place the chicken on the hot grill and cook for 5-7 minutes without moving it. Flip and continue cooking for another 5-7 minutes, or until the thickest part reaches 165°F on an instant-read thermometer.
Transfer the grilled chicken to a clean plate and let it rest for 5 minutes before slicing.
Sprinkle with chopped parsley, if desired, and serve with lime wedges.
2 tablespoons chopped fresh parsley, Lime wedges