01 - Whisk together olive oil, lemon zest, lemon juice, garlic, oregano, salt, and pepper in a bowl until well combined.
02 - Place the spatchcocked chicken in a large dish or resealable bag. Pour the marinade over the chicken, ensuring it is thoroughly coated. Cover and refrigerate for at least 2 hours, or overnight for optimal flavor penetration.
03 - Preheat barbecue to medium heat (approximately 375°F) and set up for indirect cooking. Alternatively, preheat oven to 375°F if roasting indoors.
04 - Remove the chicken from the marinade, allowing excess to drip off. Discard any remaining marinade.
05 - Place chicken skin side up on the cooler side of the grill (indirect heat). Close the lid and cook for 40-45 minutes, turning once or twice, until internal temperature reaches 165°F at the thickest part of the meat.
06 - Move chicken skin side down over direct heat for 2-3 minutes to achieve crispy, golden, lightly charred skin.
07 - Transfer chicken to a cutting board, tent loosely with aluminum foil, and allow to rest for 10 minutes before carving to retain juices.
08 - Carve the chicken and serve with lemon wedges and fresh oregano sprigs for garnish.