Put the flour in a bowl and press a depression in the middle. Crumble yeast into it, add sugar and half of the lukewarm milk. Mix with some flour. Add the remaining milk, fat, egg yolk and vanillin - sugar and knead to a smooth yeast dough.
Cover and leave to rise in a warm place for about 30 minutes. Knead yeast dough again briefly and cut into three pieces. Roll out each piece to the length and width of a box form (approx. 25 cm length; 1 1/2 litre capacity) on a floured work surface.
Place a yeast piece in the greased box mould sprinkled with breadcrumbs. Spread with plum jam and place the second pastry sheet on top. Whisk the egg yolk and cream and spread the dough thinly with it.
Sprinkle half of the nut-raisin mixture on top, press down a little and cover with the last layer of dough. Cover the cake and leave to rise for 15 - 20 minutes in a warm place. Then spread the yeast dough with some egg yolk-cream mixture and sprinkle the remaining nut mixture on top.
Sprinkle with the remaining egg yolk and bake in the preheated oven (electric oven: 175 °C/ gas: level 2) for approx. 35 minutes. If necessary, cover in between so that the raisins and nuts do not get too dark.
Leave the finished cake to cool in the mould for 15 - 20 minutes. Then carefully turn out of the mould and let it cool down completely on a cake rack. Serve dusted with icing sugar. Makes about 15 slices.