Peel and cut the onion into eight wedges and drizzle with olive oil.
Rub the chicken with honey and a pinch of salt, and put in a large roasting tin surrounded by the onions in a single layer.
Roast for 25 mins.
FOR THE WALNUT PESTO:
Put the parsley and walnuts in a food processor with a fat pinch of salt. With the motor running, dribble in the oil, chopping the ingredients coarsely.
Stop while it is still a very rough paste. (This pesto lasts about two days in the fridge.)
Serve the chicken and onions with the walnut pesto, and a scattering of pomegranate arils and a trickle of pomegranate molasses.
The pesto in this recipe is delicious with so many things - try it with pasta, duck or even venison.