To make the syrup, put the apple juice in a heavy-based saucepan over a high heat with the wine, cinnamon stick, cloves, peppercorns and star anise, if using. Bring to the boil and boil for 10 minutes, or until the mixture has reduced by about half to make a light syrup. Strain it into a bowl and leave to cool, discarding the spices.
Meanwhile, push an apple corer through from the base of each pear as far as you can without disturbing the stem; this will make it easier to remove the cores after poaching. Using a vegetable peeler or a small sharp knife, peel the pears, keeping the stalks in place.
Pack the pears closely together upright in a saucepan and pour the spiced syrup over them. Wet a large sheet of greaseproof paper and crumple it, then push it down over the top of the pears to keep them submerged.
Place the pan over a high heat and bring the syrup to the boil, then reduce the heat, cover and continue simmering for 20-30 minutes until the pears feel tender when pierced with a knife. Remove the pan from the heat and leave the pears to cool in the syrup for 2 hours to enhance their flavour.
Remove the pears from the syrup and set them aside. Return the pan to a high heat and boil the syrup for 20 minutes, or until it has reduced by about half. Transfer it to a heatproof bowl and leave for 30 minutes, or until cool. Using a small sharp knife, remove as much core as possible from the base of each pear.
To serve, place the pears on individual plates and spoon the syrup over them. Or, for an elegant presentation, slash each pear lengthways four times, almost through to the stalk, and fan them out before pouring the syrup over. Accompany with Greek yoghurt or half-fat crème fraîche, if you like.
Tip: to prepare ahead, store the syrup and pears separately in covered containers in the refrigerator after they have cooled at the end of Step 5 until you are ready to serve them.