Heat the olive oil in a large skillet over medium heat. Add the cubed beef and cook until browned on all sides. Remove the beef from the skillet and set it aside.

In the same skillet, add the diced onion, garlic, carrots, and celery. Cook until the vegetables are softened, about 5 minutes.

Sprinkle the flour over the vegetables and stir to combine. Slowly pour in the beef broth, stirring constantly to avoid lumps. Add the Worcestershire sauce, thyme, salt, and pepper. Return the beef to the skillet and stir in the frozen peas. Simmer for 10-15 minutes until the mixture thickens.

Preheat your oven to 375°F (190°C). Divide the beef filling evenly among four oven-safe ramekins. Cut the puff pastry into circles slightly larger than the ramekins and place them on top of the filling. Press the edges to seal and brush with the beaten egg.

Place the ramekins on a baking sheet and bake for 20-25 minutes, or until the pastry is golden brown and puffed.