Lemon Meringue Pie

This was one of the first recipes I ever made on my own a few years ago, it was quite difficult and time-consuming but the end result is sooo satisfying. Due to its enormous size and excellent look this would be great for a party whit lots of people. NB: If you don't have baking beans you can use rice and barley instead.
Ingredients:
For the pastry:
225g/8oz plain flour
175g/6oz butter
45g/1¾oz icing sugar
1 large free ­range egg, beaten

For the lemon filling
6 lemons, zest and juice
65g/2¼oz cornflour
250g/9oz caster sugar
6 free ­range egg yolks

For the meringue topping
4 free­ range egg whites
225g/8oz caster sugar
2 tsp cornflour

Pre­heat the oven to 180C/350F/Gas 4.

First make the pastry. Measure the flour and butter into a food processor and blend together until the mixture resembles fine breadcrumbs. Add the icing sugar, egg and one tablespoon of water and whizz again until combined to a ball.

Tip the pastry onto a work surface and roll out to a 3mm thickness. Use the rolling pin to lift the pastry up and transfer it to line a 23cm/9in loose­bottomed flan tin. Be careful not to stretch the pastry as you tuck it into the corners. Cover in cling film and place in the refrigerator to chill for 30 minutes.

Take the pastry­lined tin out of the fridge and trim the excess pastry. Press the top edge of the pastry so that it stands slightly higher than the top of the tin.

Line the pastry case with parchment and fill with baking beans. Bake for about 15 minutes then remove the beans and parchment and return to the oven for a further five minutes.

Remove from the oven and reduce the temperature to 170C/340F/Gas 3½.

For the filling, mix the lemon zest and juice with the cornflour and stir to form a smooth paste. Measure 450ml/16fl oz of water into a pan and bring to the boil. Add the lemon cornflour mixture to the hot water and stir over the heat until the mixture has thickened, then remove from the heat.