For the dough, peel and wash the potatoes and grate them finely on a clean tea towel. Squeeze the potato rasp (see handle). Mix 400 g flour, dry yeast and about 1 teaspoon salt. Add grated potatoes, egg and 100 ml lukewarm water.
First knead everything with the dough hooks of the hand mixer. Then knead vigorously with floured hands to a smooth dough. If the dough is too dry, knead in a spoonful of lukewarm water.
Cover and leave to rise in a warm place for about 45 minutes.
In the meantime cut Kabanossi into slices. Clean and wash spring onions and cut them into rings. Drain the sauerkraut on a sieve.
Line a baking tray with baking paper. Knead the soft potato dough with floured hands. If the dough is too sticky, knead in 1-2 tbsp. flour. Roll out on the baking tray to an oval flat cake (approx. 1 cm thick) with a floured dough roll or press flat with floured hands.
Let it go for about 15 minutes.
Preheat oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3). Stir crème fraîche until smooth. Season with salt and pepper and spread on the potato dough. Spread sauerkraut, spring onions and sausage on top.
Bake in a hot oven for 40-45 minutes. Cover after 30 minutes if necessary.
Cut the potato cake into pieces and serve with crème fraîche if desired.