Peel the potatoes, cut into cubes and cook in salted water. Drain and let cool slightly. Mash the potatoes and mix with egg yolks, nutmeg and salt, then let cool. Knead in the flour and work quickly into a dough. Shape into finger-thick noodles about 5 cm long, tapered at the ends, rolling them between your hands or on a board.
Cook in boiling salted water. Once they float to the surface, remove with a slotted spoon. Melt the butter, add breadcrumbs and lightly toast, then toss the Schupfnudeln in it, season with salt and serve.