Start by combining the sultanas, some sugar, and whiskey in a pan on medium heat and mix thoroughly. Leave to cool while cooking the apples in a separate pan along with some whiskey, 125g demerara sugar and a cinnamon stick.
When the apples are soft, strain them and set them aside. Once the filling is complete, roll the pastry into the thickness of a £1 coin. Pierce with a fork and blind bake for ten minutes.
At this point, you can coat it in the egg and milk mixture before returning to the oven for a further five minutes. Complete this step twice, then add the apple and sultana mixture to the pastry.
Be sure to strain any of the whiskey that the sultanas haven’t soaked up to avoid soggy pastry. Add the lid of the pastry, egg wash, and return to the oven for 20 minutes, ensuring there are steam holes in the lid.