Café Royal Cocktail Book by W. J. Tarling (1937, p.233)

1 unitegg yolk — Yolk of an Eggbase
Soda water — Syphon Sodadilution
0.5 partcream — Creamother
0.5 partalmond syrup — Almond Syrupsweetener
  1. Shake and strain, then fill up with a dash of syphon soda.

Invented by W. J. Tarling. 1st Prize International Cocktail Competition, London, 1930.