Heat olive oil in a large skillet over medium-high heat. Season the beef cubes with salt and pepper, then brown them on all sides for 5-7 minutes. Remove beef from skillet and set aside.

In the same skillet, add onion, carrots, and celery. Cook until softened for about 5 minutes. Add minced garlic and cook for another minute until fragrant.

Sprinkle flour over the vegetables and stir to coat. Gradually pour in beef broth while stirring constantly to prevent lumps. Add Worcestershire sauce and dried thyme. Return beef to skillet and bring to a simmer.

Reduce heat to low, cover, and simmer for 45-60 minutes until beef is tender and sauce has thickened. Stir in frozen peas during last 5 minutes of cooking. Let filling cool slightly.

Preheat oven to 400°F (200°C). Roll out pastry and cut circles slightly larger than individual pie dishes. Spoon beef filling into 4-6 individual oven-safe bowls or ramekins. Top with pastry circles, pressing edges to seal. Brush with beaten egg and cut small slit in center for steam to escape.

Bake for 20-25 minutes until pastry is golden brown and puffed. Let cool for 5-10 minutes before serving.