No-Bake Cake

Mix the quark with powdered sugar and sour cream (you can use a mixer on low speed, I used a slotted potato masher). Add the butter. Steam the prunes and chop them.

Line a suitable baking dish with plastic wrap and arrange a layer of biscuits (a 3x2 grid, or larger; I used 4 layers).

You can quickly dip the biscuits in coffee or drizzle them lightly. Spread the curd filling over them and add the prunes. Add another layer of biscuits, drizzle with coffee, add the curd filling, and repeat with prunes. You can spread a thin layer of filling on the very top layer of biscuits or leave it bare. I spread a little and didn't add prunes.

Carefully invert onto a serving plate, remove the plastic wrap, and frost the top and sides with cream. Dust the top with cocoa and coat the sides with crushed biscuits.