Peel and dice the onion and clove of garlic and sauté in the hot butter. Stir in chopped parsley and set aside to cool.
Cut the rolls into thin slices and pour lukewarm milk over them in a large bowl. Stir in eggs, salt and pepper. Work in the onion and parsley mixture and finally bind with a tablespoon of flour. If the mass is too mushy, it can be strengthened with breadcrumbs.
Form medium-sized dumplings with damp hands and steep in the boiling salted water for about 15 minutes more than boil.