Beat the eggs until frothy, place the flour, sugar, oil, mineral water, and baking powder on a greased tray or a baking sheet lined with baking paper. Bake at 180 degrees for 25-30 minutes. Let cool down.
Drain the juice from the mandarins. Make a cake glaze from ½ l juice. Mix this with the mandarins. Spread on the floor.
Mix the cream, vanilla sugar and cream stiffener, whip until stiff. Stir in the sour cream. Pour over the mandarins. Mix 3 tablespoons of sugar with cinnamon, spread over the cake. (Stays fresh for a long time).