Put the flour and butter in a food processor and blitz to breadcrumbs. Add the egg yolks, sugar and salt; stir well. Use your hands to combine the mixture into a smooth dough. If it feels a bit dry add a little milk.
Form the pastry into a ball, wrap it in cling film and put in the fridge to rest for 30 minutes. Once ready to use bring it out of the fridge and let it warm up a little. Roll it out on a floured surface to the thickness of a pound coin.
Pre-heat the oven to 190 C / Gas 5.
For the filling:
Melt 20g butter in a saucepan add the apples, ginger and water. Cover with a lid and cook for 10 minutes, stirring occasionally, until the apples are soft and broken down. Remove and let cool.
You are now ready to cut out your pastry circles. Cut out 12 circles using a 9cm round pastry cutter for the bases. Line a 12 hole muffin tin with these. For the lids use a 6cm round pastry cutter to cut out 12 lids; you will need to re-roll the pastry.
Once you have lined the muffin tin with the pastry bases you can add your filling. Spoon one teaspoon of caramel onto the pastry and then cover with the apples. Dampen the edges of the pastry with water and place the smaller circles of pastry on top. Press lightly to seal and pierce a small hole in the centre of each pie. Brush with the egg and sprinkle with sugar.
Bake in the pre-heated oven for 20 minutes, or until the pastry is lovely and golden. Leave to cool in the tin for a few minutes then put on a wire rack. Sprinkle with a little icing sugar. Fantastic!