Select a deep 23cm round or similar sized oval/oblong pie dish and layer up the pork, apples and onions, seasoning well with salt, pepper and nutmeg as you go. Pour over the wine or wine and stock mix.
Roll out pastry to fit the top of the pie and slightly larger to allow for the trim to be used to make a pastry border around pie dish rim. Brush the dish rim with beaten egg, stick on the pastry trim to form a border then brush this with beaten egg, and top with the main pastry. Press edges together firmly to seal, make slits or steam holes in the top and brush well with beaten egg.
Bake for approx. 1 hour to ensure meat is cooked, you may have to lay a piece of baking paper on top to prevent the pastry from browning too much after about 30 minutes. Serve hot.