The original recipe for the Blue Monday can be found in the Savoy Cocktail Book from 1930 by Harry Craddick. It also pops up again in the 1934 Official Mixers Manual by Patrick Gavin Duffy. This version is a slight variation on the original 1930s edition found in Differds Guide: The Bartender’s Bible. This variation substitutes Vanilla Vodka for Citroen Vodka as well as Vermouth for Dry Vermouth. This gives it orange and vanilla highlights with the body from the vermouth.