Preheat bbq. set bbq. to low (MOST IMPORTANT).
Cover a flat rock or brick with foil and place chicken bone side down on bbq.
Place foil covered stone on top of chicken and cook 15-20 mins. (depending on size of breasts - smaller breasts 15 mins. larger 20mins).
Carefully (can be very hot) remove stone
and flip chicken.
Wrap stone with other piece of foil
place back on top of the chicken and cook for same time as first side
this can also be prepared on a campfie, yum.