1. Prepare the Steak Filling

1. Brown the Beef: Heat the olive oil in a large frying pan over medium-high heat. Add the cubed steak and brown on all sides. Remove the meat and set aside.
2. Cook the Vegetables: In the same pan, sauté the onions, carrots, and garlic until soft, about 5-7 minutes.
3. Add the Flour: Sprinkle the flour over the vegetables and cook for 2-3 minutes to thicken the sauce.
4. Combine the Ingredients: Return the beef to the pan, and add the beef stock, tomato paste, Worcestershire sauce, thyme, salt, and pepper. Bring to a simmer and cook on low heat for 30-40 minutes, or until the meat is tender and the sauce has thickened.
5. Cool the Filling: Remove the filling from the heat and let it cool slightly before assembling the pie.

2. Make the Shortcrust Pastry

1. Combine the Flour and Butter: In a mixing bowl, rub the cold butter into the flour using your fingertips until the mixture resembles breadcrumbs.
2. Add Cold Water: Gradually add the cold water, one tablespoon at a time, until the dough begins to come together. Form the dough into a ball, wrap it in cling film, and refrigerate for 30 minutes.

3. Assemble the Pie

1. Preheat the Oven: Preheat your oven to 200°C (400°F).
2. Roll Out the Pastry: Divide the chilled dough into two portions—one for the base and one for the top. Roll out the larger portion on a floured surface to fit your pie dish.
3. Fill the Pie: Place the pastry base into the pie dish and fill with the cooled steak filling.
4. Top the Pie: Roll out the second portion of pastry and place it over the filling. Trim the edges, crimp to seal, and make a small slit in the center to allow steam to escape.
5. Brush with Egg: Brush the top of the pie with beaten egg for a golden finish.

4. Bake the Pie

1. Bake the Pie: Place the pie in the preheated oven and bake for 30-35 minutes, or until the pastry is golden brown and crisp.
2. Cool and Serve: Let the pie cool for 10 minutes before serving.