Put the raisins in a bowl and cover with the brandy. Set aside to soak for 2 hours.
Put the apples in a bowl and add the breadcrumbs, sugar, lemon rind, pine nuts, cinnamon and the raisins and their juices. Stir well.
Lay 2 sheets of the pastry on a lightly floured work surface, next to each other and overlapping by about 2.5 cm (1 inch) to form a larger sheet of pastry. Brush with melted butter, then top with the remaining pastry, brushing each layer with a little butter.
Spread the apple mixture over the pastry, leaving a 5 cm (2 inch) border. Fold the long sides over the filling. Brush with butter and roll up from a short side to form a Swiss roll.
Transfer to a baking sheet, brush with the remaining melted butter and bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 30–35 minutes until lightly golden. Combine the sifted icing sugar with a little extra cinnamon and dust the strudel. Serve hot with custard or whipped cream.