In a mixing bowl, combine the lemon zest, lemon juice, minced garlic, dried oregano, dried thyme, red pepper flakes (if using), olive oil, salt, and pepper. Whisk together until well mixed.
Place the chicken breasts in a large resealable plastic bag or a shallow dish. Pour the marinade over the chicken, ensuring all pieces are well-coated. Seal the bag or cover the dish and marinate in the refrigerator for at least 30 minutes (up to 2 hours for more flavor).
Preheat your grill or stovetop skillet over medium-high heat. Remove the chicken from the marinade, letting any excess drip off. Discard the marinade.
Grill or sear the chicken breasts for about 6-7 minutes on each side, or until the internal temperature reaches 165°F (75°C) and they have nice grill marks.
Once cooked, remove the chicken from the grill and let it rest for 5 minutes before slicing. This will help keep the chicken juicy.
Garnish with fresh parsley and serve with additional lemon wedges if desired.