• Marinate the chicken. In a large ziploc bag, combine chicken, olive oil, lemon zest, lemon juice, garlic, parsley, salt, and pepper. Seal the bag and shake it all up until well combined. Place the bag in the refrigerator and marinate for about 4 hours or overnight. 
• Prepare the grill. Preheat the grill to about 375ºF to 400ºF. Brush the grill grates with olive oil.
• Grill the chicken. Remove the chicken breasts from the marinade and place them on the hot grill; cook without touching the grill until they start to get grill marks, about 5 minutes.
• Flip. Turn the chicken breasts over, cover the grill, and let them finish cooking, about 7 more minutes, depending on the thickness of the chicken. The chicken is done when a meat thermometer registers 165 degrees Fahrenheit.
• Rest the chicken. Remove chicken from grill; cover and let rest for 5 minutes before cutting and serving.

Grill Pan Instructions

• Prep. Preheat oven to 350ºF. Grease a grill pan with cooking spray and set it over medium-high heat.
• Sear the chicken. Add the chicken and cook for 4 minutes; flip, and continue to cook for 2 more minutes, or until lightly browned.
• Finish in the oven. Place the grill pan in the oven and cook for 18 to 20 minutes or until the chicken is cooked through. Remove from oven and let rest 5 to 8 minutes before cutting and serving.