Roll out the remaining dough, stamping out 12 more circles. Use a small star cutter to stamp out a star shape from the centre of each (these will be the lids). Put a pastry lid on top of each pie, pressing the edges to seal. If you like, use a fluted 8cm cutter to neaten the shape and help seal the edges. Put the star-shaped offcuts on the tray, too. Brush the tops of the pies and the stars with the egg and sprinkle over a little sugar. Chill the pies for at least 30 mins, or up to a day. Will keep frozen for up to two months.