"Sara Murphy, no mean hostess herself, once wrote him pleading for his recipe for sole véronique"
Portrait of Sara Murphy by Picasso
Sara Murphy and her husband Gerald were expatriate American socialites, famous for their parties on the French Riviera in the 1920s. Dick and Nicole Driver in F. Scott Fitzgerald
's Tender is the Night
are thought to be based on the Murphies. Picasso, who was a friend, painted Sara Murphy several times.
Sole véronique is a famous French fish recipe that marries dover or lemon sole with tarragon, cream and grapes. See here for Delia Smith's version.