Sauté the finely chopped onion in hot oil until translucent, add the sauerkraut and the paprika cut into strips, sauté. Stir in the tomato paste, deglaze with the vegetable stock. Simmer over low heat for about 20 minutes. Then apply the creme fraiche.
Alternately fill a greased baking dish with lasagne plates and sauerkraut mixture, starting with the sauerkraut mixture when layering. Add the sauerkraut as the last layer. Finally, sprinkle cheese over the lasagna. Baked in a preheated oven at 180 degrees for about 40 minutes.