Prepare the vanilla pudding with the milk according to the package insert and allow to cool slightly. Stir it from time to time so that no skin forms.
Mash the bananas well with a fork and mix with the quark, then stir the pudding into the quark mixture and season everything with sugar. Then put everything in the cold for at least 1 hour.
(If you like it creamy, you can also whip 1 cup of cream and add it to the quark mixture at the end)