If you don’t have an ice cream maker, make the sorbet with this method: Spread the pear mixture into a shallow pan and freeze. Stir with a fork every 45 minutes. When mixture is fairly firm, pulse in a blender for a few seconds to break up the ice into finer crystals. Refreeze.
Start the poaching liquid: Add sugar, water, Poire William liqueur, ginger, vanilla bean and scrapings, lemon juice, lemon zest and pear nectar to a medium saucepan. Bring to a boil over high heat. Reduce heat to medium low and simmer poaching liquid for 5 to 6 minutes to let flavours marry.
Add pears. Cut a round of parchment paper to cover the pears completely. Pears should be immersed in poaching liquid. Over medium low heat, poach pears until tender, turning pears during the cooking process to cook the pears evenly. Poach pears for about 15 to 20 minutes. Cooking time will vary depending on how ripe the pears are.
Remove pears from the poaching liquid. Set aside to cool. Taste and adjust the poaching liquid for sweetness or tang by adding more sugar or a bit of fresh lemon juice if needed. Strain the poaching liquid, removing the ginger and vanilla bean. Let pears and poaching liquid cool. In a food processor puree the pears and poaching liquid together.
For better results, thoroughly chill the pear mixture in the refrigerator overnight. (Chilling will help in the crystallization process in the ice cream freeze.) Process the mixture in an ice cream maker according to manufacturer’s instructions. Freeze until completely frozen. Keep frozen until ready to serve. Makes about 2 cups and will serve 6 to 8. Garnish with sliced crystallized dried pear.