Preheat the oven to 375F.
Place the chicken breast side down on a cutting board. Using a chef’s knife or poultry sheers, cut along each side of backbone, separating backbone from the chicken. Remove backbone and save it for stock or discard.
Turn the chicken, breast side up facing you, on a cutting board. With the heel of your hands, press firmly against the breastbone until it cracks, and it becomes flat.
Start at the neck and loosen and lift skin around the breasts and around the tights part of the chicken. Gently pushing between skin and meat (be careful not to detach skin completely) rub salt under the skin. Place the cut butter under the skin. Sprinkle generously salt and pepper all over the cavity and the all over skin.
In a large cookie sheet spread the lemon, thyme, sliced onion, garlic and ginger to cover the bottom. Sprinkle with salt. Place the wire rack over the lemon onion mixture and place the flatten chicken, breast side up, in the middle of the rack. Add the wine and the 1 ½ cup of the chicken stock.
Roast the chicken in the preheat oven. Add more chicken stock to the cookie sheet if it starts to dry out. Rotate the chicken halfway through roasting time. Poke gently with a fork the breast at the tight junction to let out any juices. Bake for 1 to 1 ½ hours. Remove from oven and let rest for 10 minutes before carving.