Preheat the oven to 450F and line a baking sheet with parchment paper - you can cook in a cast-iron skillet instead, but you need a very large one
Zest one lemon and mince the garlic. Add butter, lemon zest, garlic, salt, parsley, and thyme to a small mixing bowl. Mix to combine thoroughly and set to the side
Spatchcock your chicken by removing the backbone, flipping over and pressing down on the breasts to lay flat with the breast side up - see instructions and video above for how to do this
Take your butter, lemon, and herb mixture and rub it under the skin of your bird. You can lift the skin on the breasts and the thighs to really pack a lot of the mixture under the skin - this is how the meat gets flavorful and juicy
Lay your spatchcocked chicken on the lined baking sheet or in a cast iron skillet. Brush olive oil all over the skin of the chicken and season liberally with salt and fresh cracked black pepper.
Place in the oven to bake for 45-55 minutes - until the thickest section of the thigh meat reads 165F on a meat thermometer. The timing will depend on the size of the bird. Our 4lb chicken took 45 minutes, a 5lb chicken took 55 minutes and a 5.25lb chicken took nearly an hour. Use that as a guide, but the temperature is the best way to know.
Remove from the oven and allow the chicken to rest for about 15 minutes before cutting into parts to enjoy!
Notes
** A 4-5 lb chicken is enough for 4 large servings.