Add the flour and icing sugar to a large mixing bowl. Add the cold, cubed unsalted butter and rub it in with your fingertips until the mixture resembles fine breadcrumbs. Add the egg yolk and 1 tablespoon of cold water, then mix with your hands or a knife until a smooth pastry dough forms. If it feels a little dry, add a tiny splash more water. You can also make the pastry in a food processor, simply pulse all the ingredients together until the dough starts to come together.
Grease a 9-inch (23cm) loose-bottomed tart tin. Roll the pastry out on a lightly floured surface to a thickness of about 1–2 coins, then carefully press it into the tart tin. Trim and tidy the edges, using any leftover pastry to patch gaps. Chill in the fridge for 30 minutes.
Preheat your oven to Gas Mark 6, 200°C (180°C fan). Line the pastry case with baking parchment and fill with baking beans or uncooked rice. Blind bake for 15 minutes. Remove the parchment and beans, then bake for another 5 minutes, or until the pastry is lightly golden and fully cooked. Set aside to cool while you prepare the frangipane filling.
To make the frangipane, add the softened butter and sugar to a mixing bowl and beat together until light and creamy. Add the eggs one at a time, mixing well after each addition. Stir in the ground almonds, plain flour and almond extract to create a smooth almond filling.
Spread a generous layer of mincemeat over the cooled pastry case, making sure it reaches the edges. Spoon the frangipane mixture on top and smooth it out with a spatula so the tart bakes evenly. Sprinkle with flaked almonds.
Bake the tart at Gas mark 4, 180c (160c fan) for 35-40 minutes, or until the frangipane is golden, risen and springs back lightly when touched. Allow the tart to cool completely in the tin.
Once cooled, remove from the tin, dust with icing sugar, slice and enjoy!
