• 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. 
• Preheat the grill to about 375˚F to 400˚F.
• Brush the grill grates with olive oil.
• 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.
• 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.
• Remove chicken from grill; cover and let rest for 5 minutes before cutting and serving.

Grill Pan Instructions

• Preheat oven to 350˚F.
• Grease a grill pan with cooking spray and set it over medium-high heat.
• Add the chicken and cook for 4 minutes; flip, and continue to cook for 2 more minutes, or until lightly browned.
• 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.