To make the base, beat the butter and sugar together in an electric mixer fitted with a paddle attachment until light and fluffy. Add the vanilla and iced water, then beat in the egg yolks one at a time, beating well between each addition. Finally, sift in the flour and stir through just until combined -- don't overmix.

Press ⅔ of the base into a 26cm (about 10-inch) springform tin, covering the base and the sides. Roll out the remaining pastry between 2 sheets of greaseproof paper for the lid, and refrigerate both while you make the filling.

To make the filling, combine the apples, sugar, water, cinnamon, and nutmeg in a large saucepan. Place over low heat and cook for 15 minutes, stirring frequently, until the apples have softened. Strain the apple mixture well and set aside to cool completely.

Preheat the oven to 180°C (350°F). Remove the pastry from the refrigerator and sprinkle the ground almonds over the base -- this helps keep it from becoming soggy. Pour the drained, cooled apples over the top, then cover with the pastry lid. Press the edges together firmly to seal, brush with the beaten egg yolk glaze, and sprinkle with a little extra sugar.

Bake for 45 to 50 minutes, or until deep golden brown. Let the cake rest for at least 10-15 minutes before slicing so the filling can set. Serve warm with freshly whipped cream.