01 - In a medium bowl, whisk together the maple syrup, Dijon mustard, olive oil, apple cider vinegar, garlic, thyme, salt, and black pepper until thoroughly combined.
02 - Place the chicken breasts in a large resealable bag or shallow dish. Pour the marinade over the chicken, ensuring all pieces are evenly coated. Seal or cover and refrigerate for at least 1 hour, or up to 8 hours for deeper flavor.
03 - Preheat your grill to medium-high heat. Lightly oil the grill grates to prevent sticking.
04 - Remove the chicken from the marinade, shaking off any excess, and discard the leftover marinade. Grill the chicken for 5 to 7 minutes per side, or until fully cooked and the internal temperature reaches 165°F.
05 - Remove the chicken from the grill and let it rest for 5 minutes before slicing. Garnish with fresh parsley and serve with lemon wedges.