Begin by preparing the poaching liquid, which forms the foundation of this elegant dessert. In a saucepan just large enough to hold the pears upright in a single layer, combine 1¾ cups granulated sugar, 5 cups water, and a few strips of lemon zest.
Heat the mixture gently while stirring until the sugar has completely dissolved, then increase the heat and boil rapidly for 2 minutes. Carefully place the 6 peeled pears (with stems left intact) into the hot syrup.
Cover the pears with a wet sheet of wax paper to prevent the tops from drying out, then bring the liquid to a boil. Reduce the heat, cover the pan with a lid, and simmer gently for 30–45 minutes until the pears are just tender. Once cooked, set the pan aside and allow the pears to cool completely in the syrup.
While the pears are cooling, prepare the blackberry sauce by combining 1 lb (500g) blackberries and ½ cup granulated sugar in a separate pan. Cook this mixture for about 5 minutes, stirring occasionally, until the juices begin to run freely.
Pass the cooked berries through a fine sieve into a bowl, pressing gently to create a thickish purée that will coat the pears beautifully.
To serve, remove the cooled pears from the syrup and pat them dry with paper towels. Present the dessert by either serving one whole pear per person or, for a more refined presentation, cut each pear in half lengthwise through the stem, carefully remove the core, and arrange 2 halves on each plate.
Drizzle the blackberry sauce generously over the pears just before serving to showcase the vibrant color and rich flavor of both components.
