Melt the butter in the microwave for the bottom. Chop the shortbread biscuits. Put both in a large bowl and stir together. Add the cocoa. With a spoon, press the mass down well in the mold and put it in the refrigerator for a short time.
Preheat the oven to 160 ° C top / bottom heat.
Mix the remaining ingredients well together to form a quark mixture, pour onto the base and smooth out a little.
Bake the cake for about 1 hour. Don`t forget your chopstick sample.