Preheat oven to 425 degrees.
Brown ground beef with onion over medium heat until cooked through. Drain excess fat and transfer meat into a bowl.
Stir potatoes, bread crumbs, coriander, salt, and Worcestershire sauce into meat. Taste for seasoning and adjust.
Add beaten egg and fresh parsley to the meat and stir to combine.
Cut four even circles out of each round of pie dough using a bowl.
Fill each round with just under ¼ C of meat filling, fold dough over the top to cover, crimp with the tines of a fork, and cut 3 small slits in the top of each pie to vent. Place pies on a baking sheet.
Bake for 15 minutes or until the edges are golden brown and top is cooked through.
Serve with beef gravy or eat plain.