To a large mixing bowl add plain gluten free flour, xanthan gum, sugar and salt. Mix well.
Add your cold cubed butter and rub in with a fork until it starts to look like breadcrumbs.
Add 1 egg and mix in using a table knife.
Add water 1 tablespoon at a time and mix well until it starts to form a dough.
Turn out onto a floured surface and knead until smooth. Wrap in clingfilm and leave in the fridge for atleast an hour.
After an hour preheat your oven to 180°C and remove the pastry from the fridge. Set aside a third of the mixture and roll out the remaining two thirds on a floured surface until it's about 1cm thick.
Cut out 12 circles (larger than your cupcake tin) and press the circles into your cupcake tin, ensuring that you press the pastry up the side of the tin.
Spoon around 1 tablespoon of mincemeat into each of the unbaked pastry cases.
Roll out the remaining third of pastry on a floured surface and use a star cookie cutter to cut out 12 stars. Place the stars on top of the mincemeat and brush with the remaining beaten egg.
Bake in the oven for around 25 minutes, until golden brown. Dust with icing sugar.