Preheat your oven to 375°F (190°C). Unroll the shortcrust pastry and carefully line a 9-inch tart pan, pressing it into the flutes. Trim any excess pastry.

Prick the base of the pastry with a fork multiple times. Line with parchment paper and fill with baking beans or uncooked rice.

Blind bake the pastry shell for 15 minutes. Remove the paper and beans, then bake for another 5 minutes until the base is sandy to the touch. Remove from oven and let cool slightly.

Reduce the oven temperature to 350°F (175°C).

Spread the sour cherry jam in an even layer over the base of the pastry case.

To make the frangipane, beat the softened butter and sugar together in a bowl until pale and fluffy.

Add the eggs one at a time, beating well after each addition, then mix in the almond extract.

Gently fold in the ground pistachios and flour until just combined.

Spoon the pistachio mixture over the jam layer and smooth the surface with a spatula or the back of a spoon.

Sprinkle the flaked almonds evenly over the top.

Bake for 30 to 35 minutes, or until the filling is risen, set, and golden brown on top.

Allow the tart to cool completely in the tin before dusting with icing sugar and slicing.