Make a kneading dough from margarine, salt, egg, flour, baking powder, sugar, vanilla sugar and finesse in the food processor and leave to rest in the refrigerator in a bowl with a lid or wrapped in cling film.
In the meantime, preheat the oven to 200 ° C.
For the filling, stir 4 egg yolks with the sugar and vanilla sugar to a frothy mixture and gradually stir in the quark, soft margarine, 2 sachets of vanilla pudding powder and the orange finesse. Now stir in the milk and finally fold in the stiffly beaten egg white with the whisk. Grease a 26 springform pan, lightly flour and line the dough with the edge and fill with the quark mixture. Bake for 15 minutes at 200 ° C and then switch the oven back to 180 ° C and finish baking for another 50 minutes. Let the cake stand for a few more minutes in the slightly open oven. Then cool completely on a wire rack. The cake falls back in easily after cooling, which is desirable.
For the fruit topping, drain the mandarin oranges through a hair sieve, collecting the juice. Dust the cooled cake with a little juice stop and cover with the well-drained mandarins.
Bring the clear cake topping with the captured juice to the boil according to the instructions on the package, but without additional sugar and spread it on the mandarins while still hot. Leave to cool in the refrigerator for at least 2 hours and only then loosen the cake ring.
Whip 1 beaker of whipped cream with whipped cream and vanilla sugar until stiff and pour into a piping bag with a star nozzle. Decorate the cake as you like.