2 litres Kefir
Pour the kefir into an ovenproof container.
Heat the oven to 100 degrees C. Put the container into the oven for about 1 hour.
It’s done when the quark-curd has thickened slightly and begun to separate from the whey. Be aware that you need to carefully stir with a spoon to see if the whey has separated or not.
Cover a large sieve with a clean kitchen towel (sterilized with boiling water!) and pour everything in the container onto the towel. Let drain for at least 1 hour, preferably longer.
Then take the whole kitchen towel and try to drain the last by hand, squeezing firmly. Keep the quark-curd in the fridge until you need it.