Pre heat oven to 220ºC (200ºC if it is a fan oven.)
Roll out your puff pastry in to a square (or unroll your shop bought puff pastry) and place on a greased baking tray.
Peel, core and slice the apples and scatter on one half of the pastry. Scatter the currants on top and sprinkle with a little ground cinnamon and sugar.
With a brush, apply some milk to the three sides around the pile of fruit, fold the large piece of uncovered pastry over and crimp.
Brush the top with milk, pierce with a knife in several places and sprinkle some sugar over the turnover.
Place in the oven and bake for 20-30 minutes until the pastry has a lovely golden colour.
Serve with cream, ice-cream or by itself.