In a large mixing bowl, measure and add; grated garlic, salt, thyme, oregano, parsley, garlic powder, onion powder and black pepper. Lastly, measure and add in ¼ teaspoon red pepper flakes - if using.
Pour in the oil, whisk until combined and set off to the side.
Working in batches, place 2 chicken breasts in a large resealable bag and use the flat side of a meat tenderizer to pound the thickest part until the chicken is an even thickness. Remove and repeat with remaining 2 chicken breasts.
Transfer the chicken to the marinade and toss to coat. Alternatively, you could add the pounded chicken breast to a resealable bag, pour the marinade over top and seal.Refrigerate for 30 minutes up to overnight.
Preheat grill to 500-550°.
Remove the marinating chicken from the fridge and set out while the grill preheats (about 15 to 20 minutes) to take some of the chill off.
Once your grill is hot, lay the chicken breasts smooth-side facing down onto the grill grates, close the lid and grill 4 to 5 minutes. Turn and repeat until fully cooked and no longer pink. Using an instant read thermometer is a great way to check doneness – the internal temperature of chicken should be 165°.
Remove, cover loosely with foil and let rest for 5 to 8 minutes so the juices can redistribute.
Serve as is next to your favorite side dishes or slice for salads, sandwiches or wraps!
