We were surprised to find that this drink probably predates blue curaçao! Famed bartender Harry Craddock used a “blue vegetable extract” along with Cointreau triple sec to create the effect.
Thankfully, mixologist gaz regan’s recipe from The Joy of Cocktails stays away from the vegetable aisle. It is tricky to find a decent blue curaçao that isn’t just sugar water; we like the versions from Giffard or Drillaud, French producers of high-quality fruit liqueurs. A good one should taste indistinguishable from quality orange liqueur when you taste it with your eyes closed, due to the use of real orange peels in the infusion process rather than artificial orange-flavored extracts.