Heat olive oil in a large pot over medium heat. Sear beef pieces until browned on all sides. Remove and set aside.
In the same pot, sauté onions, garlic, carrots, and celery for about 5 minutes until softened.
Sprinkle in flour and stir well. Slowly pour in beef broth, stirring continuously to prevent lumps.
Add Worcestershire sauce, thyme, salt, and black pepper. Return the beef to the pot and simmer on low heat for about 1 hour, until tender.
Stir in frozen peas and cook for another 5 minutes. Transfer the mixture to a baking dish.
Roll out the puff pastry and lay it over the baking dish. Crimp the edges and brush with beaten egg.
Bake at 400°F (200°C) for about 25 minutes, or until the pastry is golden brown.
Let the pie rest for 5 minutes before serving. Enjoy warm.