Preheat the oven to 180C.

Cut the block of pastry in half. Sprinkle a little flour on a clean surface then roll out one half of the pastry to line a 20cm pie dish. Lay it all the way over so the pastry overlaps the edge.

Pop it into the fridge for the moment, whilst you peel and chop the apples. Slice them into ½ cm pieces. Pat the apple slices dry with kitchen paper then put them in a large mixing bowl.

Add the sugar, flour, cinnamon, and the zest of a lemon and mix it well.

Pile the apples high into the pie base, then roll out the remaining piece of pastry.

Lay the pastry over the top and press down the edges firmly. Crimp the edges, cut away any excess pastry then cut 2-3 slits in the top for steam to escape.

Brush the pastry with the beaten egg, then sprinkle over some caster sugar.

Bake the pie for 50 minutes, then leave it to stand for at least 5 minutes before dishing it up. Serve with cream, ice cream or custard and enjoy.