First, cook the potatoes in steam, peel and press through the potato ricer.
Knead the potato mixture with egg, salt, flour and buckwheat flour to a smooth dough. With lightly floured hands, shape the dough into 12 equal-sized dumplings.
Bring salted water to a boil, add the dumplings and let them steep in it for about 10 minutes.
When the potato dumplings float to the top, lift them out of the water.