Work the butter, flour, icing sugar, salt, wine, egg yolks and sour cream together with a knife, then by hand into a dough. If too firm, add a little more sour cream.
Wrap the dough in cling film and chill for 20-30 minutes.
On a floured surface, fold the dough a few times, then roll out to about 1 cm thick and place in a parchment-lined baking tray.
Sprinkle the top evenly with the breadcrumbs.
Arrange the halved plums tightly in rows on the dough, cut-side up.
Sprinkle with the sugar mixed with cinnamon, and the ground almonds.
Bake in a 180°C (medium) preheated oven for about 30-35 minutes, until golden and crisp.
Serve lukewarm, cut into slices.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.