Using a food processor, add the flour, salt, and icing sugar and pulse to mix together. Add the cold butter and pulse until the mixture resembles coarse breadcrumbs with pea-sized pieces of butter left.

Add the egg and pulse until the mixture begins to clump together. (Do not process to the point that a large ball of dough is formed. The dough should be quite crumbly with large clumps, and should stick together when you press a piece together with your fingers.)

Bring together on a lightly floured surface with your hands, and shape into a 1-inch thick disc. Wrap in clingfilm, and chill for 1 hour. If you don't have a food processor, you can use a pastry cutter or a fork.

On a lightly floured surface, roll out the pastry to line an un-greased 23cm/9-inch fluted tart tin with a loose base. Press lightly into the tin, letting the excess pastry hang over the edge. Make sure not to stretch the dough. Chill for 1 hour.

Preheat the oven to 180C/350F/Gas 4.

Roll the pin over the top of the tin to cut off the excess pastry. Prick the base all over with a fork.

Line the chilled pastry crust loosely with foil or parchment paper, and fill with baking beans. Bake for 15 minutes, then remove the beans and foil and bake for a further 5 minutes until pale golden.

Using a handheld or stand mixer, beat together the butter and sugar until light and fluffy. Beat in the eggs, one at a time. Fold in the ground almonds and extract.

Spread the jam across the base of the pastry case, then spoon in the filling, spreading out evenly. Sprinkle the flaked almonds on top. Bake for 35 - 40 minutes or until well risen and a toothpick inserted comes out clean.

Leave to cool completely in the tin before slicing and serving.