Peel and wash the potatoes and cook in salted water for about 25 minutes
Crumble the yeast, dissolve in lukewarm milk with sugar. Mix starch, whole flour and about 1 teaspoon salt. Press a depression in the middle. Add yeast milk and mix with some flour mixture from the rim. Cover the pre-dough and let it rise for about 20 minutes in a warm place
Drain the potatoes and press or mash them with a potato ricer. Leave to cool a little. Add 200 ml lukewarm water, binding agent and possibly caraway seeds to the pre-dough. Knead everything. Leave to rise for about 45 minutes
Knead the dough, form into a loaf. Leave to rise for a further 20 minutes on a baking tray lined with baking paper. Bake in a hot oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for 45-55 minutes