Cut the rolls into small pieces and place in a bowl. Sauté the onion and parsley in oil in a pan and add to the rolls. Stick the egg in a cup and only add half of it to the bread dough. Pour some warm milk over it and knead vigorously with your hands. Season to taste with salt and nutmeg. If the dough is too soft, add a little more breadcrumbs and knead again.
With moistened hands, form either 1 large or 2 small dumplings out of the dough and let it steep in salted water for approx. The water must not boil bubbly after the dumplings are in the pot.
Sauce:
Clean the mushrooms and cut them into slices. Sauté the onion with the mushrooms in oil. Dust with the flour and stir well, then add the cream with the milk. Season to taste with granulated broth, salt and pepper and reduce briefly. Finally add the chopped parsley.