Preheat the oven to 450 degrees F. Set out a large rimmed baking sheet and brush the surface with oil.
Set a small sauce pot over medium heat. Add the Coca-Cola, ketchup, salt, and all spices. Stir well. Allow the mixture to simmer until it thickens to the consistency of BBQ sauce. Stir every few minutes.
Meanwhile spatchcock the chicken: Look and the bird carefully to determine where you see the breast meat. Then flip the chicken over and find the backbone.
Use strong kitchen shears to cut alongside the backbone, from one end of the bird to the other. Then cut along the other side of the backbone to remove it completely. Keep the shears very close to the backbone as to not cut off any meat.
Open the cavity of the chicken to find the breastbone. Now cut a shallow incision through the flexible bone, from one end to the other, yet not all the way through the breast meat and skin on the other side. This allows the chicken to be flattened.
Place the chicken breast-side-up on the rimmed baking sheet. Push the breasts down to flatten the chicken. Pull the drumsticks down and together to create the classic spatchcock shape. Then deal with the wings… On some chickens, the tips of the wings have already been trimmed off. In this case, leave them as-is. However, on other chickens, the wings tips are intact and are likely to burn before the chicken is cooked through. You can either cut them off at the joint, or tuck them up and under the breasts.
Pat the chicken dry with paper towels, including any excess juices on the baking sheet. Brush half the sauce over the chicken and place it in the oven.
Roast the chicken for 20 minutes. Then brush the remaining sauce over the chicken and bake another 15 minutes, or until the interior temperature reads 165 degrees F.
If the top of the chicken isn't as dark as you like, you can place it under the broiler for 3-4 minutes at the end. Watch it closely as to not burn the skin.