Grease the cake tin with lard.
To make the pastry place the lard and water in the small pan and heat until the lard has melted.
Sift the flour into a large mixing bowl and season with salt and freshly ground black pepper.
Make a well in the centre of the flour and pour in the hot lard mixture.
Use a wooden spoon to mix in and then use your hands to bring to a dough.
Turn the dough out onto a lightly floured work surface and knead for a few minutes until the dough is very smooth.
Form the dough into a ball, wrap in clingfilm and place in the fridge for 30 minutes.
To make the filling, place the streaky bacon in the frying pan and heat up until it starts to brown and render up some fat. Transfer the bacon to the small bowl, leaving the fat in the pan.
Add oil if there isn’t enough bacon fat and sauté the onions until translucent and just starting to take on colour. Take off the heat and set aside.
Remove the pastry from the fridge, unwrap and place on a lightly floured work surface.
Take a third of the pastry, roll into a ball and wrap in clingfilm. This will make the lid of the pie. Set aside.
Roll out the remaining pastry and line the cake tin with it, bringing it up over the edge of the tin.
Place a layer of apples at the bottom of the pie, cover with a layer of sliced onions and top with a layer of bacon. Repeat these layers until the pie is full, seasoning each layer.
Roll out the remaining pastry to make the lid of the pie.
Brush the top edges of the pie base with beaten egg and place the lid on top, crimping the pastry to form a seal at the edges.
Decorate the pie with shapes made from the pastry offcuts and stick on with beaten egg.
Make a hole in the centre of the pastry lid. Make a funnel with a folded piece of kitchen foil and place in the hole ensuring the walls of the funnel are flush to the pastry.
Place in the fridge for an hour to harden the pastry.
Preheat oven to 160C/320F/gas 2.5.
Brush the top of the pie with the beaten egg and make a hole in the centre.
Remove from the fridge and glaze the top of the pie with beaten egg.
Place in the oven for 2 hours until the pastry is golden brown, and the filling cooked through. Allow to cool and transfer from the tin to a serving dish.
