Preheat oven to 200C/400F/Gas 6. Roll out the prepared pastry on a lightly floured surface to about 3mm/1/8in thick. Cut out 18 rounds with the large cutter and roll out again if necessary to cut out 18 lids with smaller cutter. Line the patty tins with the larger rounds.
Fill the pastry to about half their depth with mincemeat taking care not to overfill. Dampen the edges with a little water and cover with the pastry lids. Seal the edges well.
Brush the tops with water and dredge with sugar. Make two small cuts in the top of each pie. Bake for 15-minutes or until golden brown.
Remove the tins and leave to cool and then dredge with a little more sugar.