Heat the oil in a medium saucepan then add the onion and garlic then cook stirring often until the onion is soft. Add the mince and cook stirring to break up any lumps. This will take about 10 minutes.
Sprinkle the flour over the meat and cook for 1 minute, this should make the mixture appear dry and crumbly.
Add the tomato sauce, Worcestershire sauce, beef stock and additional stock cube. Simmer while stirring for 10 minutes until the sauce is thick. Season with salt and pepper. Remove from the heat and cool completely.
Preheat the oven to 200 degrees C. Grease a muffin tray.
Cut the shortcrust pastry to line the base and sides of the muffin tray. Fill the pastry with the meat mixture being careful to avoid spilling any on the edges.
Cut the puff pastry to make the top for the mini pies. Brush the shortcrust pastry edges of the pies with water to moisten and top with the puff pastry. Press the pastry edges together to secure. Brush the top with beaten egg.
Bake the pies in the preheated oven for 10 minutes then reduce the oven temperature to 180 degrees C then bake for a further 15 minutes or until the pastry is puffed and golden. Serve the pies immediately .