Preheat oven to 400 degrees and line two baking sheets with parchment.
Roll out pie crusts and use a 8-9" tart pan or other pan, inverted, to cut the dough into 4 large circles. You may have to reform and roll the dough between cuttings to get all four circles. Lay 2 dough circles on each parchment lined baking sheet.
Pile about 1 1/2 cups of the meat and potato mixture (with juices) onto one half of each dough circle. Spread evenly over that half of the dough circle, leaving about 1/2" rim around the edge for crimping. Sprinkle some sea salt and pepper over the meat and potato mixture.
Use a pastry brush to brush the 1/2" rim of pastry with some of the beaten egg - this will serve as "glue" to seal the pastry edges.
Gently fold the "blank" side of each dough circle over the meat and potato filling side, matching the edges of the pastry to create a half-circle shaped hand pie. Use your finger to press and seal the edges of the pastry together, fluting them for decoration if desired.
Once each hand pie is formed, use a very sharp knife to lightly score the top of each pie.
Use a pastry brush to cover the surface of each hand pie with beaten egg.
Bake for 25-30 minutes or until crusts are golden and firm to the touch.