For the elderberry cake, knead a dough from grated potatoes, an egg, a pinch of sugar and flour and roll out on a baking sheet. Sprinkle thickly with ripe elderberries and place a few pitted plums in halves on top.
Mix curd cheese, 1 tablespoon flour, salt and egg and spread on the dough.
Finally, spread a mixture of sour cream, egg and 2 tablespoons of flour on the topping by tablespoonfuls and bake in the oven at about 220 °C.
Sprinkle the elderberry cake with sugar while it is still hot.