Whip the cream very stiff with the cream stiffener. Mix the sour cream, yoghurt and tangerines briefly with the hand mixer, fold in the cream.
Dip the ladyfingers one at a time in tangerine juice and cover the bottom of a baking dish with them. A layer of cream on top. Keep doing this until everything is gone. The last layer should be a layer of cream (2 layers of biscuit and 2 layers of cream fit exactly in a 28 x 18 cm baking dish).
Finally, sprinkle with some grated chocolate.
Well chilled it tastes particularly good on hot days, the next day almost even better and not only as a dessert, but also as a substitute for the cream cake.