In a large mixing bowl, combine the flour, instant yeast, granulated sugar, vanilla sugar, and salt. Whisk them together.

Add in the quark cheese, egg, and melted butter to the dry ingredients and mix until a cohesive dough forms. Be careful not to overmix.

Knead the dough for 5 to 8 minutes until it becomes smooth and elastic. Dust extra flour if too sticky but avoid adding too much.

Allow the dough to rise in a warm place for 1 hour or until it has doubled in size.

Once risen, punch down the dough and divide it into small pieces, rolling each into balls about 1 to 2 inches wide.

In a deep pot, heat your frying oil to 350°F (175°C).

Fry the quark balls in batches for about 3 to 4 minutes or until golden brown, turning occasionally.

Remove them from the oil and let them drain on paper towels.

While still warm, roll them in the cinnamon-sugar mixture.