Roll out the dough, place in the tin, prick firmly with a fork. Spread the nuts over the pastry base.
Cut the apple into slices, arrange the apple slices on top.
Place the sugar, butter and flour in a bowl, mix well by hand until the mixture becomes crumbly, sprinkle on top of the apples.
Approx. 35 mins. in the lower half of an oven preheated to 200°C. Remove from the oven, allow to cool slightly, slide onto a cooling rack and leave to cool completely.