BILLY BY, BILLI BI
Billy by is a mussel soup of mussel stock, white wine, onions and celery with fresh cream. Can be served hot or cold.
Probably named after William B Leeds, an American industrialist and regular customer at Maxim's, where chef Louis Barthe created Billy By. Another story says it was created at a farewell dinner for an American officer named Bill who was at the Normandy landings.