Preheat the oven to 200°C. Grease a 20cm square baking tin.
Roll out each pastry sheet on a lightly floured surface. Cut each pastry sheet into two 10cm squares. Place the squares in the prepared baking tin, overlapping slightly.
In a medium saucepan, mix together the cornflour, caster sugar and vanilla extract. Gradually add the milk, stirring constantly. Cook the mixture over medium heat until it thickens and boils, stirring constantly.
In a separate bowl, whisk the egg yolks until light and fluffy. Gradually add the hot milk mixture to the egg yolks, stirring constantly. Return the mixture to the saucepan and cook over low heat for 2 minutes, stirring constantly.
Pour the custard over the pastry squares. Bake for 25 minutes or until the custard is set and the pastry is golden brown. Allow to cool before slicing into pieces.
Dust with sifted icing sugar before serving.
Interesting Facts
Vanilla Slice is also known as custard slice or vanilla slice.
It is believed to have originated in Australia in the 19th century.
It is a popular dessert in many countries around the world.