Sauté the onions in the olive oil until soft. Add all the rest of the ingredients except the chicken and wine and simmer gently for 10 to 15 minutes. Add the wine and heat through. Cool. Marinate the chicken halves in this mixture for 2 to 3 hours, turning them frequently to be sure they are well bathed.

Meanwhile prepare a charcoal fire. Place the chicken halves on a rack 3 to 4 inches from the coals and charcoal broil. Arrange bone side down and broil for 12 to 15 minutes. Brush with sauce, turn, and broil for another 12 to 15 minutes. Test for doneness by puncturing the thigh joint with a fork. When the juice runs clear or slightly pink, not red, the chicken is cooked. Do not overcook, or it will be dry and tasteless.