Place the liqueur, Poire Williams in a large bowl. If you are not using any alcohol, add a little extra lemon juice to help prevent the fruit discolouring. Prepare the pears one at a time. Peel, cut into quarters and cut out the cores. Toss in the lemon juice. Place on a medium-high heat, watch the pan carefully at this stage, moving it around if one area is browning faster than another. As soon as the sugar has caramelised, remove from the heat, scater the juniper berries in the caramel.