Mix quark, milk, sugar, vanillin sugar, cinnamon, lemon juice and zest until smooth. Whip cream until stiff and fold in
Finely crumble the brown cake. Divide 3/4 between 4 dessert glasses. Drizzle 1 teaspoon of liqueur over each and place 1 tablespoon of cranberries on each. Cover with the quark cream. Sprinkle remaining cranberries and biscuit crumbs over it. Decorate with mint and icing sugar if desired
If you can't get brown cake, you can crumble and layer either spiced specula or gingerbread without chocolate coating
Trifle is also ideal as a spontaneous dessert, because all the ingredients can be kept in stock. By the way: It goes even faster with 500 g cream quark instead of low-fat quark and cream