If using fresh apples, peel, core and slice the apples (or open tins and stir in the sugar and cinnamon). put in a pan with a little water and simmer until soft.
Remove from the heat and sprinkle with the sugar and cinnamon. Leave to cool.
To make the pastry, sift the flour into a large bowl. Cut the margarine into cubes and quickly rub into the flour using your fingertips until the mixture resembles breadcrumbs. Sprinkle in the sugar and water and mix, using a round bladed knife, until the mixture begins to stick together in large lumps.
With one had, collect the dough together to form a ball. Turn out onto a clean work surface and gently knead and shape into an even ball.
Place the apple into suitable tins, roll out the pastry and lay on top of the apples. Crimp the edges of the pastry. Cut a steam vent in the middle, then brush the pastry with water and sprinkle with extra sugar. Bake in a preheated oven for 30-35 minutes.