2. Bring the sugar and water to a boil in a small saucepan over high heat. Let cool.
3. When the pears have been in the freezer 20 minutes and are about half frozen, place in a blender with the water and sugar mixture. Puree and strain, pressing with a rubber spatula to release the juices.
4. Freeze the strained pear mixture in an ice cream machine according to the manufacturer's instructions.
5. Store in the freezer until ready to use. The texture is best if it is eaten within 24 hours. After that it becomes very hard and icy, but it can be melted and refrozen in an ice cream machine.