In a large frying pan, heat the olive oil over medium-high heat. Add the chopped onion and garlic and cook until they become translucent.
Add the ground meat to the pan and cook until browned, breaking it apart with a spatula as it cooks.
Sprinkle the plain flour over the meat and stir well to combine. Cook for a few minutes to remove the raw flour taste.
Stir in the tomato paste, Worcestershire sauce, and dried mixed herbs. Season with salt and pepper to taste.
Slowly add the beef or vegetable stock, stirring continuously, until the mixture thickens and becomes a flavorful gravy. Simmer for a few more minutes, then remove it from the heat and allow it to cool slightly.
Grease a 4-cup (1-liter) pie dish or individual pie dishes.
Line the pie dish(es) with one sheet of puff pastry, pressing it into the sides and leaving some overhang.
Spoon the meat filling into the pastry-lined dish(es).
Place the second sheet of puff pastry on top of the filling. Trim any excess pastry hanging over the edges and press the edges together to seal the pie.
Brush the beaten egg over the top pastry for a golden finish.
Using a sharp knife, make a small slit in the center of the pastry to allow steam to escape.
Place the pie(s) in the preheated oven and bake for 25-30 minutes or until the pastry is golden brown and puffed up.
Remove from the oven and let it cool slightly before serving.
Serve your Aussie Meat Pie with tomato sauce (ketchup) or your favorite condiments.
Enjoy your homemade Aussie Meat Pie, a hearty and comforting Australian classic!