Heat olive oil in a large skillet over medium-high heat. Add the beef cubes and brown on all sides, about 5-7 minutes. Remove the beef and set aside. In the same skillet, add onions, carrots, and celery. Cook until softened, about 5 minutes. Add garlic and cook for another minute.

Sprinkle flour over the vegetables and stir to coat. Gradually add beef broth while stirring constantly to prevent lumps. Add Worcestershire sauce, thyme, and pepper. Return the beef to the skillet and bring to a simmer. Reduce heat to low, cover, and cook for 20 minutes until beef is tender.

Preheat oven to 400°F (200°C). Stir frozen peas into the beef mixture. Roll out puff pastry and cut into circles slightly larger than your ramekins or individual pie dishes. Spoon beef filling into each dish, leaving about ½-inch space at the top. Place pastry circles over the filling, pressing edges to seal. Brush with beaten egg and cut small slits in the top for steam to escape.

Bake for 20-25 minutes until the pastry is golden brown and puffed. Let cool for 5 minutes before serving. The filling will be hot, so be careful when serving.