Preheat the oven to 160°C/325°F/gas mark 3.
Place the pear quarters in an ovenproof dish large enough to hold them without overlapping, add water to half cover the pears, then add the star anise and drizzle over 2 teaspoons of the agave syrup. Bake for about 25 minutes, or until tender.
Meanwhile, whizz the cashews with the vanilla extract and 225 ml (7½ fl oz/scant 1 cup) of water in a blender until smooth and creamy. Transfer to a serving bowl.
When the pears are cooked, remove them from the dish with a slotted spoon and set aside. Pour half the cooking liquid into a pan with 2 of the star anise and the remaining agave syrup and place over a high heat for about 5 minutes, stirring constantly, until the liquid becomes thick and syrupy.
Serve the pears with the syrup, cashew cream and a little of the remaining cooking liquid.