For the bread dumplings, cut the rolls into thin slices and soak them in lukewarm milk for 15 minutes.
In the meantime, wash the rocket, dry it well and chop it finely. Clean the leek and cut into very fine rings (if necessary cut in half again beforehand), then sauté in 1 tablespoon of melted butter over a low heat for 2 - 3 minutes.
Now squeeze out the rolls and mix with the eggs, rocket, leek and butter. Season with salt, pepper and nutmeg. Form approx. 8 - 12 dumplings from the finished mixture and let them steep in slightly boiling salted water for 15 - 20 minutes. If necessary, reduce the heat a little so that the water simmer only slightly and the bread dumplings don`t fall apart.
For the sauce, remove the sand from the mushrooms with a brush (do not wash!) And cut into slices. Braise in 2 tablespoons of melted butter.
Peel the onion and chop finely. Chop the parsley and lemon zest. Stew together with the mushrooms for 10 minutes. Finally add the cream and bring to the boil again briefly. Season with mustard, salt and caraway seeds.
Arrange on plates and serve hot.
Note: The recipe can also be served well as a warm starter. To do this, shape the dumplings a little smaller. Place 1 - 2 small dumplings on each plate with a spoonful of cream mushrooms and serve.