Pre heat oven to 210 C. Line oven trays with baking paper and place one pastry on each tray. Prick with a fork and bake 5-10 minutes. Allow pastry to cool. Combine custard powder, sugar and cream in a saucepan over medium heat. Gradually add milk, stirring continuously until thick. Add vanilla. Put custard into a bowl and allow to cool. Put cling wrap over custard to stop a skin forming. Cut pastry to fit a brownie pan. Layer the custard over the pastry and then add other cut pastry sheet. Make icing by combining butter and icing sugar and 2-3 drops of red food gel colouring. Mix together till smooth and not too thick.. Spread over pastry sheet and allow to set. Put in fridge to set, then cut into 12 slices. You can put what ever topping you like.