For the flash cake, pour cream into a bowl. Add sugar, vanilla sugar and eggs and mix well. Then stir in flour, baking powder, salt and lemon zest.
Spread the finished dough on a greased and floured baking tray and bake in the oven preheated to 200° C on the middle shelf for 10 minutes.
In the meantime, prepare the icing. Mix the soft butter with the sugar, vanilla sugar and milk and then add the almonds.
Remove the cake from the oven and spread the icing evenly on top. Now bake the flash cake again with top heat for another 10 minutes.