For the pastry, put the flour, sugar and lemon zest in a bowl. Rub in the butter until the mixture resembles breadcrumbs. Add the beaten egg and stir with a round-bladed knife until the mixture forms a dough.

Set aside one-third of the pastry for the lid. Roll out the remaining pastry on a lightly floured surface until the thickness of a pound coin and 5–7cm/2–3in larger than the pie dish. Lift the pastry over the rolling pin and lower it gently into the pie dish.

Press the pastry firmly into the dish and up the sides, making sure there are no air bubbles. Chill the pastry in the fridge while you prepare the filling.

Preheat the oven to 200C/180C Fan/Gas 6. Place a baking tray into the oven to preheat.

For the filling, mix the sugar, cinnamon and cornflour in a large bowl. Stir in the apples until coated.

Put the apple filling in the pie dish, making sure that it rises above the sides of the dish (particularly in the middle). Brush the rim of the pastry with beaten egg.

Roll out the reserved ball of pastry to make the pie lid. Cover the pie with the pastry lid and press the edges together firmly to seal.

Using a sharp knife, trim off the excess pastry, then gently crimp all around the edge. Make a few small holes in the centre of the pie with the tip of a knife or a skewer. Glaze the top with beaten egg.

Lightly knead the pastry trimmings and re-roll. Cut into leaf shapes and arrange all around the edge of the pie, slightly overlapping each other. Glaze with more egg.

Sprinkle the pie with sugar and bake in the centre of the oven for 45–55 minutes or until golden-brown all over and the apples are tender.

Serve warm or cold with cream, custard or ice cream.