Potatoes in the bowl just covered with water and put on closed lid, soften. Melt yeast cubes in 100 g of water. Stand for 10 min.
Sift flour (type 1050) into a suitable bowl. Add 150 g whole wheat flour and make a bulge in the center.
Pour the dissolved yeast into it. Stir with a little bit of flour to a thin paste. Let stand for 15 minutes.
Cool the boiled potatoes a little bit and peel them. Weigh out 400 g of them. Grate on a coarse grater.
The potatoes should still be warm, but no more than lukewarm, when you add them to the stew.
Add salt, caraway seeds or bread spices. Prepare a dough with a wooden spoon or possibly a wooden spoon while adding 250 g of water in portions. Stir this at the beginning in the baking bowl until all the flour is incorporated. Then knead on a dry surface to form a smooth dough. Do not add more water. The dough must be very dry! Knead for 5 minutes. Shape into a ball. Return to the baking bowl.
Cover with a wet dishcloth and leave in a warm place for 1 1/2 hours. Knead again. If the dough sticks to the surface (this depends on the quality of the potatoes), dust it lightly with flour.
Shape the dough into a ball. Cut it into two pieces, as large as possible on the spot. Knead each part again. Depending on the size of the bread baskets, shape the dough into round or elongated loaves.