Preheat the oven to 425°F.

Line a rimmed baking sheet with aluminum foil and position a roasting rack in the pan.

Remove and discard the giblets from the cavity of the chicken.

Crush the garlic cloves with the side of a knife and discard the papery skins.

Take one garlic clove and rub it firmly over the entire surface of the chicken. Place all of the crushed garlic in the cavity of the chicken.

Liberally season the chicken inside and out with salt and black pepper.

Stir the softened butter and olive oil together in a small bowl until mostly combined. With clean hands, rub the mixture all over the chicken and under the breast skin.

Place the chicken on the roasting rack breast side up. Tie the legs together with kitchen twine, and tuck the wing tips beneath the body of the chicken.

Separate the onion into two parts and place into the cavity of the chicken, along with the parsley, thyme, and lemon half.

Roast the chicken on middle rack of oven until the thickest part of the chicken breast reaches an internal temperature of 160°F, 60-80 minutes.

Check to see that chicken is done. Remove from oven or add time as needed.

Allow chicken to rest for 10 minutes before carving and serving. Leftovers may be refrigerated for 3-4 days or frozen for up to 2 months.