Grate the 10 potatoes finely using a food processor or potato grater.
In a large bowl, combine 100 ml lukewarm water and 100 ml lukewarm milk, then dissolve the 2 packs yeast in the mixture.
Add the grated potatoes, 200 g sugar, 2 tablespoon salt, 7 eggs, 1 packet raisins, and 1 kg flour. Stir vigorously with a mixing spoon until the dough is sticky and falls from the spoon (add more lukewarm milk or water as needed).
Cover the bowl and let the dough rise for 4-5 hours. Every 60 minutes, stir the dough vigorously.
Divide the risen dough into 4 equal portions.
Heat goose fat or sunflower oil in a large pan over medium heat.
Pan-fry each portion until golden brown.
Transfer to a warm oven (75°C / 170°F) and keep warm until serving.
Serve with your choice of liver sausage, butter, beet cabbage, or jam.