Preheat the oven to 360°F/180°C. In a large bowl, combine flour, sugar and a pinch of salt. Make a well in the middle of the mixture. Add fresh yeast and a few tablespoons of lukewarm milk into the well. Combine the milk and yeast with a little bit of flour from the walls of the well. Cover the bowl and let the dough rest for approx. 15 min. in a warm place.
Add butter, eggs and the rest of the milk to the dough and knead everything together (you can use your hands) until it forms a smooth dough. Cover the bowl and let it rest again, approx. 30-45 min, until it has doubled in size.
On a lightly floured surface, knead the dough one last time and roll it out into a rectangular shape.
In a bowl, combine quark, vanilla and sugar. Depending on your taste, you can add more or less sugar. Spread quark on the dough and evenly distribute blueberries on top. Roll dough into a tight log and cut into 1.5 cm-wide discs.
Grease a springform pan and place the rolls inside. No worries if there's some space in between the rolls, they will continue to rise a little more. Sprinkle a few berries on top and let rest briefly. Bake in the preheated oven until done and lightly golden, approx. 15-20 min.
Take the rolls out of the oven and let cool. In the meantime, combine freshly squeezed lemon juice and confectioners sugar for a simple glaze. Drizzle the glaze on top of the rolls and garnish with more fresh berries. Enjoy!