Using a large knife or kitchen shears, cut along both sides of the backbone of the chicken and remove it.
Lay the chicken skin-side up and press the breastbone to flatten the chicken.
Alternately, the chicken can simply be cut into serving pieces.
Combine the remaining ingredients in an electric blender or food processor and puree until smooth.
Combine the chicken and the marinade in a non-reactive bowl or large plastic bag and marinate refrigerated at least 4 hours or overnight.
Cook the chicken over hot coals or under a preheated broiler, turning every 10 minutes and basting with the marinade, until charred and the juices in the thigh run clear when pricked with a fork, 30 to 45 minutes.