For the pastry, Sieve the flour and salt into a bowl, Rub in the margarine or butter until the mixture resembles fine breadcrumbs. Add the cold water to the flour mixture. Using a knife, mix the water into the flour, using your hand to firm up the mixture. The pastry should be of an even colour and suitable consistency for rolling. Divide the pastry into two halves. Take one half and roll it out so that it is big enough to cover a 20cm/8in enamel or aluminium plate. Trim the edges with a knife using the edge of the plate as your guide.
Alternatively you can buy your ready made pastry and all you have to do is split it into two halves, roll it out and ensure that it fits your plate.
Peel, core and slice some Cooking apples. Tip put into cold water after peeling to prevent going brown)
Cover the pastry with the sliced apples and sprinkle with sugar to taste.
Roll out the other half of the pastry. Moisten the edge of the bottom layer of pastry (use a little milk) and place the second piece on top.
Press down on the pastry edges, making sure that they are properly sealed. Trim off any excess pastry with a knife in a downward motion, again using the plate as your guide.
Prick the surface of the pastry lightly before placing the pie in the oven. Cook for 30-40 minutes or until pastry is lightly golden.
When cool dust with caster sugar and serve on its own or with custard.