Whizz the flour, icing sugar and butter together in a food processor until they form small crumbs.
Add the egg yolk and 1 tablespoon of cold water and process briefly to bring the pastry together (or you can do this by hand in a large mixing bowl, rubbing the butter into the flour and sugar, then bringing it all together with the liquid).
Wrap the pastry ball in clingfilm and chill in the fridge for 30 minutes. Preheat the oven to 190ºC, fan 170ºC, gas mark 5.
Once your pastry has chilled, roll it out on a floured surface and use a fluted round pastry cutter to cut out 16 rounds (roughly 9cm each), these will be the bottoms of your mince pies.
Press the rounds into a 12 hole bun/cupcake tin (use 2 tins if you have them, if not you can bake in batches). Lightly prick the bases with a fork.
Mix the mincemeat with the orange zest and whisky, and drop teaspoons of the mincemeat onto the pastry bases.
Re-roll the remaining pastry and cut out shaped lids for your mince pies (try using star, Christmas tree or holly leaf cutters).
Brush the tops with milk and sprinkle over the caster sugar. Bake in the preheated oven for 20 minutes, or until the tops are golden brown.
Allow to cool slightly in the tins, then remove to a cooling rack. Serve warm with lashings of cream or brandy butter, or let cool completely and store in an airtight container.
Cook's tip: Mince pies are perfect for making ahead and stashing in the freezer. Make as above up to step 8, then open freeze in the tins for 2 hours until firm. Transfer the frozen pies to plastic freezer bags, label and seal - these can be kept frozen for up to 3 months. When you're ready to cook, preheat the oven as above, pop the frozen pies back into the bun tins and glaze as above. Bake for 25 minutes or until golden.