Start this recipe by preparing the mincemeat. Put the brown sugar, port and fresh cranberries in a saucepan and heat till the sugar has dissolved. Add the spices, currants, raisins, dried cranberries, grated apple, orange zest and juice and simmer for 20 minutes on a low heat. When cooked, add the brandy, honey and essences and mix well. Next, line a greased 25cm deep flan tin with the sweet pastry. Spread the apple and cranberry mincemeat all over the sweet pastry base, and flatten out with a palette knife. Next, make the Viennese biscuit topping by beating together the butter, icing sugar and vanilla essence in a bowl till light and fluffy. Slowly mix in the plain flour and corn flour. You should end up with a thick cake mixture. Place the Viennese biscuit mixture in a piping bag fitted with a large star nozzle, and pipe a lattice design over the top of the mincemeat. Place the tart in the oven at 190`c, and bake for roughly 25-30 minutes, or until the Viennese biscuit topping just begins to go a golden colour. Take the tart out of the oven and leave to cool completely before serving. The cranberry and apple tart with piped Viennese biscuit can be served cut into large wedges with a scoop of vanilla ice-cream.