Preheat oven to 190C. Combine butter, sugar, salt and flours in a food processor and whiz until mixture resembles fine breadcrumbs. Add egg and water and process until mixture just comes together. Form dough into a disc, wrap in plastic wrap and refrigerate for 30 minutes.

Divide dough in half. Roll out one half on a lightly floured surface and line a round fluted 22cm flan tin with removable base. Cover and refrigerate for 30 mins.

For the filling

Combine apples in a large saucepan with sugar and water and cook over medium heat for about 10 mins or until soft. Drain and cool.

Spoon apples into prepared pastry case and brush edge with a little water or milk. Roll out remaining pastry on a lightly floured surface until large enough to cover filling, cover pie and then press pastry edges to join. Trim edge.

For the icing

Combine icing sugar, lemon rind and juice and just enough egg white to make a thick paste. Spread icing over pastry and sprinkle top with almonds.

Place pie on a hot oven tray and bake for about 40 mins or until pastry is golden and cooked. Cover loosely with foil if top browns before pastry is cooked.

To serve 

Serve warm or cold with thick cream.