1. Roll out the pastry, line a flan tin and bake blind for 15-20 minutes at 200°C, 400°F, mark 6.
2. Peel and core the apples and cut them into slices.
3. Put them into a saucepan with the sugar and water and cook until soft.
4. Either mash the apples or rub them through a sieve.
5. Separate the eggs. Beat the yolks and mix with the apples adding nutmeg.
6. Whisk the whites into a stiff meringue, with half of the castor sugar.
7. Fold in the rest of the castor sugar.
8. Put the apple mixture in the pastry case, top with the meringue, and cook for 15-20 minutes at 170°C, 325°F, mark 3.