Preheat the oven to 425. Make 5 to 6 aluminum foil balls about the size of a baseball and place them on a large rimmed baking sheet. Set aside.
In a small bowl, mix the butter, salt and pepper. Set aside.
Remove your chicken from it's packaging, pat it dry with paper towels, remove the giblet bag from the cavity if there is one and discard it or set it aside.
Holding on to the neck, cut down either side of the spine all the way to the end and remove it.
Turn the chicken breast side up and using the heel of your hand, press down between the breasts until you hear a small crack and the chicken flattens out further.
Using your hands, separate the skin from the meat of the chicken by sliding your hands under the skin as far as you can without tearing it.
Pat the chicken dry again with paper towels, then using a spatula, slide 1 tablespoon of the butter mixture under the skin of each side of the breast meat and spread it out by rubbing over the outside of the skin with your hands.
Divide the remaining tablespoon between each of the thighs in the same way.
Transfer the chicken on top of the foil balls and roast 20 minutes, then reduce the heat to 400 and roast 25 to 30 minutes more until a thermometer inserted in the thigh reads 165.
Allow your chicken to rest, uncut on the foil for 10 minutes before slicing and serving.