Place the flour and salt in a large bowl and add the spread. rub in with your fingertips until it resembles fine breadcrumbs. Stir in the Splenda then gradually add ice water, a drop at a time, until the pastry comes together into a ball. Wrap in clingfilm and refrigerate for an hour.
Preheat the oven to 200C/400F/gas mark 6. Roll the pastry out thinly on a lightly floured surface and use a 9cm round cutter to cut out 12 circles of pastry.
Press the rounds of pastry into a 12 hole muffin tin, they won't come all the way to the top of the cavity. Fill each one with a spoonful of the mincemeat (you won't need all of the mincemeat).
Re-roll the pastry scraps and cut out 12 star shapes. Place a star on top of each pie then bake for 20-25 minutes until pale golden.
Leave the pies to cool in the tin for five minutes then carefully turn them out onto a wire rack to cool completely.