Step 1: Prepare the Beef Filling

1. Heat 1 tablespoon olive oil in a large pot over medium-high heat. Add the beef cubes and sear for 4-5 minutes until browned on all sides. Remove from the pot and set aside.
2. Add another 1 tablespoon olive oil and sauté the onion and garlic for about 2 minutes until fragrant.
3. Stir in the mushrooms and cook until softened, about 5 minutes.
4. Add the tomato paste and cook for another minute to enhance its flavor.
5. Return the beef to the pot and sprinkle 1 tablespoon of flour over the mixture, stirring well. This helps thicken the sauce.
6. Pour in the red wine (if using) and beef broth, scraping the bottom of the pan to release any browned bits.
7. Stir in Worcestershire sauce, thyme, rosemary, salt, and pepper. Bring to a boil, then reduce heat to low and let it simmer for 1.5 to 2 hours, stirring occasionally.
8. If using, stir in the peas in the last 5 minutes of cooking.

Step 2: Preheat the Oven and Prepare the Crust

1. Preheat your oven to 375°F (190°C).
2. Roll out the puff pastry or shortcrust pastry on a lightly floured surface. If making individual pies, cut the pastry into smaller rounds to fit the pie dishes.

Step 3: Assemble the Pie

1. Pour the cooled beef filling into a pie dish.
2. Drape the pastry sheet over the top, pressing down the edges to seal. Trim any excess pastry.
3. Use a fork to crimp the edges for a decorative touch.
4. Brush the top with the beaten egg for a golden, shiny finish.
5. Cut small slits in the top to allow steam to escape.

Step 4: Bake and Serve

1. Bake in the preheated oven for 35-40 minutes until the pastry is golden brown and crisp.
2. Let the pie cool for 10 minutes before slicing. Serve warm and enjoy!