Step 1 In a saucepan, gently heat, stirring occasionally, all fruit mince ingredients until sugar has dissolved. Continue cooking over a low heat for 15 minutes, until fruit has plumped up. Spoon into a bowl and set aside to cool for at least 30 minutes.
Step 2 Meanwhile, sift flour and polenta into a large mixing bowl. Add table spread and rub into flour mixture with your fingertips until the mixture resembles fine breadcrumbs.
Step 3 Using a table knife, stir in egg and 2 tablespoons cold water until mixture clumps together.
Step 4 Form pastry into a ball with your hands. Knead lightly on a work surface dusted with gluten-free flour, until smooth. Wrap pastry in cling wrap and chill in the fridge for 30 minutes (this makes it easier to roll).
Step 5 Preheat oven to 170°C. Roll out pastry to 3mm-thickness between two sheets of lightly floured baking paper.
Step 6 Peel away baking paper. Use a 7–8cm round cutter to cut out 24 pastry rounds.
Step 7 Use 12 of the pastry rounds to line a 12-hole mince pie or muffin tin (use a fish slice to lift the pastry into the tin). Fill each with cooled fruit mince. Press remaining pastry rounds over each mince pie and seal pastry edges together with a fork. Cut two holes in tops of each pie to allow steam to escape.
Step 8 Bake for 15–20 minutes. Allow pies to cool in tin. Remove from tin, then dust with icing sugar.