Step 1: Prepare the Beef

1. Season the Beef: In a large bowl, toss the cubed beef with 2 tablespoons of plain flour, salt, and freshly ground black pepper. Ensure the beef is evenly coated. This step helps to brown the beef nicely and thickens the gravy later.
2. Brown the Beef: Heat the vegetable oil (or beef dripping) in a large, heavy-based pot or Dutch oven over medium-high heat. Working in batches to avoid overcrowding the pot, brown the beef cubes on all sides until nicely seared and browned. Browning the beef is crucial for developing deep, rich flavors. Remove the browned beef from the pot and set aside.

Step 2: Sauté the Vegetables

1. Sauté Onions and Carrots: Add the chopped onions to the pot and cook over medium heat, stirring occasionally, until softened and translucent, about 5-7 minutes. Add the sliced carrots and continue to sauté for another 5 minutes until they begin to soften slightly. Sautéing the vegetables releases their sweetness and builds the flavor base of the filling.
2. Add Aromatics: Stir in the tomato paste and dried thyme and cook for 1 minute more, allowing the tomato paste to caramelize slightly and the thyme to become fragrant.

Step 3: Create the Filling

1. Deglaze the Pot: Pour the beef broth into the pot, scraping the bottom to loosen any browned bits (fond) that have stuck to the pot. This adds depth of flavor to the gravy.
2. Add Worcestershire Sauce and Bay Leaves: Stir in the Worcestershire sauce and add the bay leaves.
3. Return Beef to the Pot: Return the browned beef to the pot, ensuring it is mostly submerged in the broth.
4. Simmer and Braise: Bring the mixture to a simmer, then reduce the heat to low, cover the pot tightly, and let it simmer gently for 2-2.5 hours, or until the beef is incredibly tender and easily shreds with a fork. Slow braising allows the beef to become meltingly tender and the flavors to meld together beautifully. Check occasionally and add more broth if necessary to keep the beef submerged.

Step 4: Prepare the Pastry (Rough Puff Pastry)

1. Combine Dry Ingredients: In a large bowl, sift together the plain flour and salt.
2. Add Butter: Add the cubed cold butter to the flour mixture. Using your fingertips or a pastry blender, quickly rub or cut the butter into the flour until the mixture resembles coarse breadcrumbs, with some larger pieces of butter remaining. It’s important not to overwork the butter; you want visible pieces for flakiness.
3. Add Ice Water: Gradually add the ice water, a tablespoon at a time, mixing lightly with a knife or your fingertips until the dough just comes together. Be careful not to add too much water; the dough should be slightly shaggy but not sticky.
4. Form and Chill Dough: Turn the dough out onto a lightly floured surface and bring it together into a rough rectangle. Wrap the dough in plastic wrap and chill in the refrigerator for at least 30 minutes.
5. Rolling and Folding (Turns): This is where the lamination happens to create layers. On a lightly floured surface, roll the chilled dough into a rectangle about three times as long as it is wide. Fold the top third of the dough down to the center and the bottom third up and over the top, like folding a letter. This is one “turn.” Wrap the dough in plastic wrap and chill for another 30 minutes. Repeat this rolling, folding, and chilling process 4-6 times in total, chilling for at least 30 minutes between each turn. The chilling is crucial to keep the butter cold and prevent it from melting into the dough.
6. Final Chill: After the final turn, wrap the dough and chill for at least 1 hour, or preferably overnight, before using.

Step 5: Assemble and Bake the Pie

1. Preheat Oven: Preheat your oven to 200°C (400°F).
2. Remove Bay Leaves: Once the beef filling is cooked, remove the bay leaves and check the seasoning. Adjust salt and pepper to taste. If the gravy is too thin, you can thicken it slightly by mixing a teaspoon of cornstarch with a tablespoon of cold water and stirring it into the filling. Simmer for a few minutes until thickened. Let the filling cool slightly before assembling the pie.
3. Roll Out Pastry: Divide the chilled pastry dough in half, slightly larger for the pie base and smaller for the lid. On a lightly floured surface, roll out the larger piece of pastry to a size slightly larger than your pie dish. Carefully lift and place the pastry into the pie dish, gently pressing it into the base and sides. Trim any excess pastry hanging over the edge.
4. Fill the Pie: Pour the cooled beef filling into the pastry-lined pie dish.
5. Roll Out Pastry Lid: Roll out the remaining pastry for the lid to a size slightly larger than the top of the pie dish. Place the pastry lid over the filling. Trim the edges and crimp them to seal the pie. You can use a fork to press the edges together or create a decorative crimp with your fingers.
6. Egg Wash and Vent: Brush the pastry lid with egg wash (if using) for a golden brown finish. Cut a few slits in the top of the pastry lid to allow steam to escape during baking. This prevents the pastry from becoming soggy.
7. Bake: Bake in the preheated oven for 30-40 minutes, or until the pastry is golden brown and cooked through, and the filling is bubbling hot.
8. Rest: Let the pie rest for 10-15 minutes before serving. This allows the filling to settle slightly and makes it easier to slice.