Slimmed-down Vanilla Slice

Preheat your oven to 200°C. Cut the pastry sheet in half and place on a baking tray. Bake for 10 minutes, or until golden and puffed. While the pastry is cooking, make the custard. In a saucepan, whisk together the cornflour, sugar, and a little of the milk to form a paste. Gradually whisk in the remaining milk. Cook over medium heat, stirring constantly, until the custard boils and thickens. Remove from the heat and stir in the vanilla extract. To assemble, place one sheet of pastry in the bottom of a square tin. Pour over the custard and top with the second sheet of pastry. Sift the icing sugar over the top. Refrigerate for at least 2 hours before slicing and serving.