Make a purée with the potatoes, and while still warm stir in the butter. Add the demerara sugar, flour and ginger to make a dough. Divide the mixture into two portions and roll out one half to fit the bottom of a
Peel and slice the apples and put them on the pastry with the caster sugar (you may need a little more depending on the tartness of the apples), the raisins, cinnamon and cloves.
Roll out the remaining pastry and cover the top, leaving a slit open. Bake at