Beat the butter and both sugars together in a stand mixer until soft and combined, or using an electric whisk until light and fluffy, about 5 mins. Crack in the eggs, one at a time, beating well after each addition. Mix in the vanilla, flour and bicarb until no pockets of flour remain. Chill the dough for at least 30 mins, or up to 24 hrs so the flour can absorb the liquid.

Line two large baking trays with baking parchment. Divide the dough into 50g balls, and flatten out in the palm of your hand. Add 2 tsp of the mincemeat to the centre of each one, and fold in the corners of the dough to enclose the mincemeat. Carefully roll back up into a ball and arrange on the baking trays, well spaced apart. Chill for at least 1 hr before baking to firm up. Will keep chilled for up to three days, or frozen for up to three months.

Heat the oven to 180C/160C fan/gas 4 and bake for 12-14 mins, swapping the trays over halfway to ensure even browning, until the edges are golden and set, and the middle is still gooey. Leave to cool completely on the trays. Will keep in an airtight container for up to five days.