Rub the cold butter into the pastry flour until crumbly. Stir in 35 g sugar, the egg yolk and 1 tablespoon cold water. Add only enough extra water to form a cohesive dough. Flatten, wrap and chill 30 minutes.

Heat the oven to 375°F (190°C). Roll the pastry on a lightly floured surface and line a 9-inch tart tin, pressing gently into the corners. Trim the edge. Prick the base, line with parchment and fill with pie weights. Place on a baking sheet.

Bake 15 minutes. Carefully lift out the weights and parchment, then bake 5–8 minutes more until the base looks dry. Reduce the oven to 350°F (180°C). Allow the shell to cool slightly while preparing the filling.

Beat the softened butter and 125 g sugar until light. Beat in the eggs one at a time, then fold in ground almonds and 20 g flour until combined.

Spread jam thinly over the pastry base. Spoon the almond mixture over it in small dollops, then smooth gently without mixing the layers. Scatter flaked almonds on top.

Bake 30–35 minutes, until golden and the center is set with no wet batter on a skewer. Shield the top loosely with foil if it browns too quickly. Cool in the tin for at least 1 hour before removing and slicing. Refrigerate leftovers promptly and use within 3–4 days.