Remove neck and giblets from the cavity if they are included.
Place chicken on a cutting board, breast side down so the backbone is facing up. Using scissors, cut along each side of the backbone to remove it completely (reserve the bone for broth or gravy if desired).
Flip chicken over so the breast side is up. Using your palms, press on the breast bone to flatten it. You should hear it crack as it flattens. Fold the wing tips under the chicken.
Arrange on a large rimmed baking sheet and brush with olive oil. Cover generously with seasonings.
Roast chicken for 45-50 minutes or until it reaches a temperature of 165°F internally.
Remove from oven and loosely tent with foil. Rest at least 15 minutes before carving.