Directions

1. Heat the oil in a large skillet over medium-high heat. Add beef stew meat, and cook until browned on the outside. Add the onion; cook and stir until tender, about 5 minutes. Stir in the mushroom gravy mix and 1 cup of water. Season with Worcestershire sauce, salt, and pepper. Turn heat to low, and simmer for 20 to 30 minutes.
2. Preheat the oven to 400 degrees F (200 degrees C). Transfer the beef mixture to a casserole dish. Roll out the puff pastry to cover the top of the casserole dish. Press edges onto the rim of the dish to seal. Whisk together the egg and 1 tablespoon of water in a small cup using a fork. Brush over the top of the pastry.
3. Bake for 20 minutes in the preheated oven, until the pastry is puffed and golden brown.