Let the berries thaw. Mix with the vanilla, sugar, linseed and the cranberries and mash with the hand blender. If you want, you can also puree the mixture, this results in a different consistency.
Layer the berry mixture alternately with quark or yoghurt, or a mixture of both, in 2 glasses. You can mix the berries into the quark and stir gently. Squeeze the orange and pour the juice into the top of the cups.
I personally prefer low-fat quark because it is particularly firm and has a nice consistency. If you like it more liquid, you can also use yogurt.