In a large skillet, add pork until fully cooked about 8 minutes, breaking up with wooden spoon. Drain off any excess fat.
Stir in stock, onions, garlic, mushrooms, celery, salt, pepper, cinnamon, cloves, allspice and thyme. Bring to a boil and reduce heat to a simmer, stirring occasionally. Simmer for about 30-40 minutes until there is a little bit of liquid left.
Stir in bread crumbs and parsley. Adjust the seasonings if necessary. Set aside to cool.
Prepare the pastry crust, and set in the refrigerator for 20-30 minutes to rest.
Roll out one disc of pastry to fit a 9 inch pie plate. Lay the pastry on the bottom of the pie plate. Spoon filling into pie shell. Cover the top with pastry and trim and create flute edges to seal.
Brush beaten egg over pastry. Cut decorative shapes from remaining pastry and arrange on top or makes slits and an opening for the center before laying onto the pie to allow stream to escape.
Bake at 375°F for 40-45 minutes or until golden brown. Let cool for 10-15 minutes before serving.