Fillet the fish.
Peel and dice the onion.
Cook the onion in butter until transparent.
Put the fish through a food grinder.
Add the onion, egg whites, cream, and bread crumbs.
Put the mixture through the food grinder again.
Add the salt and pepper and form the mixture into dumplings.
Place the fish dumplings in a greased casserole and add the hot meat broth.
Cover the dish and bake it at 350°F for 20 minutes.