Knead 375 g flour, starch, baking powder, 125 g sugar, lemon zest, eggs, salt and 225 g butter to a smooth dough and chill for 30 minutes. Mix 75 g sugar, marzipan and rum to a spreadable mixture.
Mix the remaining sugar, flour, butter and cinnamon into fine crumbles. Crumble the lady fingers. Roll out the dough on a floured work surface to 2 dough plates (35x30 cm). Spread the marzipan mixture on the dough plates.
Spread raisins, sponge crumbs and hazelnuts on the dough plates, roll up from the longer side and chill for 1 hour. Whisk the egg yolk and milk and spread on the dough rolls. Sprinkle with the crumbles and cut into wide pieces.
Place the cake pieces on a greased baking tray. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 15-20 minutes. Remove the bobbes, let them cool down a bit and dust them with icing sugar.