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, carrots, and celery. Cook until the vegetables are softened, about 5 minutes. Add the minced garlic and cook for another minute.

Sprinkle the flour over the vegetables and stir to coat. Slowly pour in the beef broth, stirring constantly to avoid lumps. Add the Worcestershire sauce, dried thyme, salt, and pepper. Bring the mixture to a simmer and cook until it thickens.

Return the cooked beef to the skillet and add the frozen peas. Stir to combine and let the filling simmer for another 5 minutes.

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 the tops 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.