Mix the low-fat quark with whipped cream and sugar until creamy.
Peel the banana, cut into slices and place on the bottom of dessert bowls or the bottom of a baking dish. Spread half of the cream on top. Chop up the Russian bread and sprinkle half of it on top. Mix the rest of the cream with the raspberries and add some rum. Fill into the bowls and finally sprinkle with Russian bread again.
Tip: You can also use whipped cream, but then you have to add 1 pck.