Follow these easy steps to create your own amazing Aberdeen Beef Pie:

1. Preheat Oven: Begin by preheating your oven to 375°F (190°C).

2. Brown the Beef: Heat the vegetable oil in a large pot over medium heat. Add the beef cubes, seasoning with salt and pepper. Brown on all sides, then remove and set aside.

3. Sauté Onions and Garlic: In the same pot, add the chopped onion. Sauté for about 5 minutes until it becomes translucent. Add garlic and cook for another minute.

4. Make the Gravy: Stir in the flour, allowing it to absorb the fats for about 1-2 minutes. Gradually add the beef stock, stirring constantly to avoid lumps.

5. Add Seasonings: Mix in the Worcestershire sauce, thyme, and mustard (if using). Bring to a boil, then reduce heat and simmer for about 10 minutes.

6. Add Vegetables: Add the diced potatoes and carrot to the pot. Return the browned beef to the mixture, simmering for an additional 30 minutes, or until the beef is tender.

7. Cool Filling: Once the beef is cooked, remove the pot from heat. Let the filling cool slightly as this will make it easier to handle later.

8. Prepare the Pie Crust: Roll out the bottom pie crust and place it into a pie dish, ensuring it covers the bottom and sides.

9. Fill the Pie: Spoon the beef filling into the prepared crust.

10. Top with Crust: Cover with the top crust, sealing the edges well. Use a sharp knife to make a few slits in the top for steam to escape.

11. Brush with Egg Wash: Brush the top crust with the beaten egg for a beautiful golden finish.

12. Bake: Place the pie in the preheated oven and bake for about 40-45 minutes, or until the crust is golden brown.

13. Cool Before Serving: Remove the pie from the oven and allow it to cool for at least 15 minutes before slicing and serving.

By following these steps, you will have created a delicious Aberdeen Beef Pie that is sure to impress!