To make the pastry: put the flour and cinnamon into the bowl of a food processor. Add the butter and pulse until it looks like very fine breadcrumbs. Sprinkle in the sugar and 3 tbsp cold water, and pulse until the mixture starts to clump together, about 30 secs. Tip the mixture onto a board and gently squeeze the pastry until it comes together into a ball – add water if it feels dry. Wrap the pastry in cling film and chill for 30 mins.
Heat oven to 190C/fan 170C/gas 5. Roll the pastry on a lightly floured surface to the thickness of £1 coin. Using a 7cm cutter, cut out 10-12 discs and use to line a 12-hole bun tin with them. Use a 6cm cutter for the lids, or use a 6cm star cutter to make star shapes. Chill both.
Make the mincemeat: put all the ingredients into a food processor and pulse on and off until evenly chopped. Spoon 1-2 tsp into each tart, dampen the edge of the pastry bottom with water and sit a smaller pastry disc or star on top. Using scissors, snip a hole in the lid, if you’ve made round tops. Bake for 12-15 mins until golden brown. Lift onto a wire rack to cool and dredge with icing sugar.