To make the walnut sugar, place the walnut, sugar and cinnamon in the bowl of a food processor and process until finely chopped. Set aside.Cook the pumpkin in a saucepan of boiling water for 15 minutes or until tender. Drain, place in the bowl of a food processor and process until smooth. Set aside to cool. Once cooled, add the maple syrup, eggs, cream and nutmeg and whisk to combine. Set aside.Place the flour, butter and icing sugar in the bowl of a food processor and process until mixture resembles fine breadcrumbs. While the motor is running, add the egg yolks and vanilla. Add the water and process until the dough just comes together. Turn out onto a lightly floured surface and gently bring together. Flatten into a disk, wrap in plastic wrap and refrigerate for 1 hour.Preheat oven to 160°C (325°F). Roll the pastry out between 2 sheets of non-stick baking paper to 3mm thick. Cut 8 x 15cm rounds from the pastry and use to line 8 x 9½cm lightly greased pie tins. Trim the edges and prick the base with a fork. Refrigerate for 30 minutes. Line the pastry cases with non-stick baking paper, fill with baking weights and blind bake for 10 minutes or until light golden. Remove the paper and the weights and brush the inside of the pastry shells with eggwhite. Place the pie tins on a baking tray, pour in the pumpkin mixture and bake for 30 minutes or until just set. Top pies with the walnut sugar to serve. Makes 8.