Easy American-style apple pie with a crisp sugar-crust. Best served with a big scoop of vanilla ice cream.
1.To make the pastry put the flour and butter in a bowl. Use your fingers to rub the two together. Stop when you have a mix of breadcrumb-sized and pea-sized lumps of butter (this will give you a flakier pastry). Stir in the icing sugar and a pinch of salt. Add the iced water spoon by spoon, mixing with a butter knife as you add until it clumps together into a dough. Wrap in clingfilm and rest for 30 minutes in the fridge.
2.Heat the oven to 190C/fan 170C/gas 5. Cut the pastry into 2, making one piece slightly bigger. Roll out the larger piece and use to line a 20cm x 3½ cm deep metal pie tin.
3.Mix the cinnamon, demerara sugar and cornflour together well. Put the apple slices in a bowl and toss with the cornflour mix. Pile into the lined tin then dot with butter.
4. Roll out the rest of the pastry to make a lid. Cover, trim and crimp together the edges. Make a steam hole in the middle (decorate the top with the off-cuts if you like). Glaze the top of the pie with egg, chill for 15 minutes then glaze again (this will give you a deep golden crust). Sprinkle the surface of the pastry with more demerara then cook for 40 minutes until crisp and golden. Serve with a scoop of ice cream.