Mix all the marinade ingredients together
thoroughly, then rub the marinade all over the chicken. Put the onion
and lemon half inside the chicken, along with any remaining marinade.
Cover and leave to marinade overnight in the refrigerator.
Place the chicken, breast side up, on a
rack in a roasting tin and roast in a preheated oven, 160oC
(325oF), Gas Mark 3, for 40 minutes, then turn the chick over
and roast for a further 40 minutes.
Finally, increase the heat to 220oC
(425oF), Gas Mark 7, turn the chicken so that it is breast
side up again and roast for 20 minutes, until it is cooked through.
Remove the chicken from the oven and allow it to stand for 10 minutes