Dutch Stewed Fish

Cook a large fish with 1 onion, 2 stalks of celery, parsley, a tablespoonful of butter, salt and pepper until done. Remove fish to a platter. Add 2 chopped pickles, the juice and rind of a lemon, 1/2 cup
of vinegar. Mash the yolks of 2 boiled eggs with 1 raw egg, a teaspoonful of prepared mustard and a tablespoonful of butter. Add to the sauce and boil. Lay the fish in the boiling sauce ten minutes;
then serve.