Cheap tesco pork pies are made form bacon.. Bite into any pork pie and the filling is pink then its made from bacon..
grey filling = Proper Pork PIE!
That said I used to make and sell my own when I was butchering, customers used to queue out of the door for them when they were hot! Dont think i often had many left to sell cold.
The hole in the top of a decent pork pie is there to pour the jelly into once baked, to fill the gap left by the shrinkage of the meat when cooked…… mmmmmmmmm pies!!!!!!