Divide the dough into two pieces, one slightly larger than the other. Between two sheets of parchment, roll the larger piece of dough paper into a rough 12 × 16-inch (30 × 40-cm) rectangle, about ¼-inch (5 mm) thick. Transfer to a baking sheet and carefully peel off the top sheet of parchment paper (reserve to roll out the second piece of dough). Cover the base with the filling, leaving about a ¾-inch (2-cm) border.
Place the second piece of dough on the reserved sheet of parchment paper and top with another sheet. Roll into a rough rectangle slightly smaller than the first (big enough to cover the filling), about ¼-inch (5 mm) thick. Remove the top layer of parchment paper and carefully invert over the empanada base—this is most easily done between two people, both holding one corner of the parchment paper in each hand. That way you can hold the sheet with the dough facing down over the base (the dough sticks to the paper) and center it well before setting it down. Peel off the parchment paper.
Fold the bottom edges of the dough over the top and seal by pressing your finger around the seam, making a dimpled border. Pierce the top of the dough all over with a fork to allow steam to escape, making sure the tines go all the way through.
Brush the surface of the dough with beaten egg, then bake for 30–40 minutes, until golden.
Let cool for about 10 minutes on the baking sheet, then carefully transfer to a cooling rack with the parchment paper underneath (once again, this is easiest with two people).
Let cool to room temperature, then cut into squares.
Serve with ice-cold lager, or with vermouth over ice with a slice of lemon and a few anchovy-stuffed olives (as pictured below).