Combine the pastry flour, sugar and salt in a large bowl. Rub the cold cubed butter into the dry ingredients with your fingertips until the mixture resembles coarse breadcrumbs.

Mix in the egg yolk and add just enough cold water for the dough to hold together when pressed. Bring together gently without kneading. Flatten into a disk, cover and refrigerate for 30 minutes.

Heat the oven to 375°F (190°C). Roll the pastry on a lightly floured surface into a circle large enough to line a 9-inch (23 cm) removable-base tart tin. Ease it into the corners without stretching, trim the edges and prick the base with a fork.

Set the tin on a baking sheet. Line the shell with baking paper and fill with pie weights. Bake for 20 minutes, carefully lift out the paper and weights, then bake for about 5 minutes more until the base looks dry and lightly golden. Let cool slightly. Reduce the oven to 350°F (175°C).

Beat the softened filling butter and sugar until pale. Beat in the eggs gradually, then fold in the ground almonds, filling flour and almond extract. Do not taste the raw mixture.

Spread the jam evenly over the slightly cooled shell. Add the almond filling in small spoonfuls, spreading gently so the jam stays underneath. Scatter the flaked almonds over the top.

Bake for 30–35 minutes until the filling is golden, the center is set and a skewer inserted into the almond layer comes out without wet batter. Shield loosely with foil if the top browns early.

Cool completely in the tin on a rack, allowing about 1 hour. Remove the tin sides carefully and cut into eight wedges. Cover and refrigerate leftovers; use within 3 days.