In a large bowl whisk together the quark, eggs, sugar and vanilla sugar.

In another bowl sieve together the flour, salt and baking powder.

Start adding the dry mixture slowly to the batter until thoroughly combined and it comes together.

Let the dough rest for about 15 minutes before frying.

Fill a large pot with vegetable oil, pour enough oil so that the quarkbällchen have enough space to cook in, about 7 cm. Heat the oil to about 170°C; you want the oil to be hot enough so that you reduce the cooking time avoiding that they get soggy, but at the same time you don't want the oil too hot that it burns the outside and leave the inside raw.

Meanwhile prepare a bowl with sugar, set aside.

Using a piping bag, ice cream scoop or two teaspoons, spoon the dough carefully into the oil and let it cook for about 2 minutes on each side until they puff up and get a golden colour.

Once they are cooked through, remove the doughnuts with a slotted spoon and place on some paper towels to drain the excess oil and let cool for a few seconds.

Toss the doughnut balls in the sugar until well coated.

Repeat until you have used up all the batter. Ideally serve them immediately when they are still warm.