Melt 100 g butter in a pot and let it cool down. Put flour and yeast into a mixing bowl and mix. Add 100 g sugar, vanillin sugar, salt, lemon zest, buttermilk, egg and liquid butter and knead with the dough hooks of the hand mixer for 3-5 minutes to a smooth dough. Cover and leave to rise in a warm place for about 30 minutes. Knead again briefly. Grease the fat pan of the oven (approx. 37x32 cm). Roll out the yeast dough on a slightly floured work surface to the size of the baking tray.
Cover the baking tray with the dough and let it rise for another 15-20 minutes. Press the remaining butter in flakes into the dough. Bake in the preheated oven (electric: 175 °C/ gas: level 2) for 30-35 minutes. In the meantime chop the almonds coarsely. Roast in a pan without fat until golden brown. 10 minutes before the end of the baking time, spread remaining sugar and almonds on the cake. Let it cool down