Place apples in saucepan with sugar and water and bring to boil. Reduce heat and simmer for approximately 10 minutes until tender. Cool to room temperature.
Sift flour and icing sugar in bowl and rub in butter. Add enough water to mix to a firm dough. Roll out two thirds of the pastry on a lightly floured surface until large enough to line a 20cm spring form tin.
Spoon cooled apple filling into pastry case. Roll out remaining pastry, brush edge of pie with egg white, cover with pastry and press edges of pastry together firmly. Trim the excess pastry and cut a few slits in the top of the pastry, then brush with remaining egg white. Sprinkle with the tablespoon of castor sugar.
Place pie in a moderately hot oven (210-230°) for 20 minutes, then reduce heat to moderate (180-200°) and bake for a further 30 minutes or until golden brown. Stand for 30 minutes.
This pie is delicious served with double thick cream.
