Mix yeast cubes with 20 g sugar until the yeast is liquid. Knead 500 g flour, milk, 80 g sugar and eggs in a large bowl. Add about 2/3 of the lemon juice, a pinch of salt and the liquid yeast. Knead with the dough hooks of the hand mixer for about 5 minutes on the lowest setting, then knead for about 5 minutes on the middle setting to a smooth dough. Then add 75 g fat in pieces and knead the mixture for another 3-5 minutes. Chill yeast dough overnight
For the crumble dough, mix 275 g fat, 175 g sugar, remaining lemon juice and a pinch of salt with your hands. Halve the mixture. Fold 200 g flour into the first mixture and knead the dough into crumbles with your hands. For the second dough, first mix 200 g flour with cocoa powder and then fold into the second mass. Also knead this with your hands to crumbles
Wash the plums, dab dry, halve and stone them. Knead the yeast dough again briefly with your hands and roll out rectangularly (approx. 40 x 60 cm) on a floured work surface. Place the dough on a greased, floured fat pan of the oven (32 x 39 cm) and press the edges slightly. Spread plums in rows on the dough with the cut surface facing upwards so that they overlap slightly. Then sprinkle both crumbled doughs alternately over the plums. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 30 minutes until golden brown
Waiting time approx. 12 hours