- Finely crumble 4 Zwieback toasts, and put the rest of the Zwieback toasts into a large bowl. Heat the milk to lukewarm, add a pinch of salt, and pour over the Zwieback toasts. Soak for 20 minutes.
- Peel the onion, dice fine, and sauté in melted butter until translucent. Add the onion, parsley, eggs, Zwieback crumbs, and flour to the milk-soaked Zwieback toasts and stir vigorously to make a smooth dough. Let rest for another 20 minutes.
- Form dumplings with moistened hands and cook in boiling salted water for about 20 minutes. Drain and serve. Tastes great with a mushroom ragout with cream sauce.