Unroll pie crusts. On work surface sprinkled lightly with flour, roll each crust to diameter of 12 inches. Using round cutter, cut five 4 1/2 inch circles from each crust. Place rounded tablespoonful beef filling on half of each dough circle. Fold in half, and press edges with fork to seal. Place on ungreased cookie sheet. In small bowl, beat egg and milk with whisk until blended. Brush on empanadas. Cut holes in tops to vent.