Warm milk in a medium pot to about 40 °C. This step is optional, and it is useful, when the bread rolls are really hard. Do not overheat the milk.
Beat eggs into the milk. Mix well.
Cut bread rolls into halves in length.
Soak bread roll halves into the milk mixture for a few minutes. The bread rolls should be thoroughly soaked with milk.
Press out as much liquid as possible from the rolls. The rolls should still be moist.
Coat the moist bread rolls in bread crumbs.
In a frying pan, pour in 2 tablespoons of cooking oil.
Over a medium heat, place the rolls into the pan and cook them until both sides turn gold-brown.
Mix cinnamon powder with sugar. Coat the Karthäuser Klöße with the cinnamon-sugar mixture.
Serve the Karthäuser Klöße with vanilla sauce.