Sift flour and icing sugar into a mixing bowl. Add in salt to mix. Gradually blend in butter with a fork until the mixture resembles fine breadcrumbs.
Stir in water and mix well into a dough. Wrap up dough in cling film wrap and chill in the refrigerator for 3040 minutes before rolling out. Cut the rolledout pastry to fit four 11cm fluted pie pans.
Prick with a fork and chill in the refrigerator for 30-40 minutes. Bake blind at 190°C for 1015 minutes.
Leave to cool completely.
For the filling: Peel and shred apple and add lemon juice to mix. Leave aside. Cream butter, sugar and eggs until light. Fold in sifted flour and cocoa powder.
Stir in shredded apple, cinnamon powder and chopped walnuts. Mix till well blended.
Pour filling mixture onto the prepared pie pans and spread evenly with a spatula. Sprinkle chopped walnuts on top and bake in preheated oven at 180°C for 2530 minutes or until golden brown and cooked through.