Remove the pastry from the refrigerator 20 minutes before use.
Preheat the oven to 200 C / Gas 6. Finely chop the steak and set aside.
Boil the kettle. In a a jug or bowl add the gravy granules and just enough hot water to make into an extremely thick gluey type of paste. Mix well, season with pepper, add the steak, mix well and set aside to cool.
Remove pastry from outer wrapper but do leave on the baking paper contained inside.
Cut into 8 even portions. Prick over 4 that you are using for a base and cut to indent (not to cut through) a small border (see picture).
Using a pastry brush, brush around the borders lightly with the beaten egg.
Divide the cooled steak and gravy mixture between four servings (ideally a heaped tablespoon per bake is sufficient). Spread gently onto the base, taking care not to spread past the border.
Carefully add the pastry top and press down or crimp to seal the pockets so that filling does not escape whilst baking.
Gently score diagonal lines on the top. Brush with beaten egg. Repeat with remaining pastry. Gently lift keeping the baking paper under and place onto a baking tray.