Have ready 3 x 750ml pie dishes - either round or oval.
Combine prepared apples with juice and rind of the lemon, sugar, nuts and cinnamon, mix well and pile into pie dish.
Divide pastry into 3, roll out each piece large enough to cover dish with some room to spare. With a sharp knife cut strips of pastry from the edges of the pastry and use to form rims on the pie dishes. Brush edge with water to help pastry to stick, then brush pastry rim with water.
Top with pastry, press down edges to form a good seal and trim off excess with a sharp knife, reserve trimmings. Knock up and flute edges of the pie, make a small hole in centre to allow steam to escape.
Re-roll trimmings and cut out leaves or other shapes of your choice and use to decorate pie tops. Brush all over with water and sprinkle with Demerara sugar.
Bake for 20 minutes then lower heat to 180ºC/ 350ºF/ Gas Mark 4 and continue cooking for further 15 minutes until the pastry is golden.