We were surprised to find that this drink probably predates blue curaao Famed bartender harry craddock used a blue vegetable extract along with cointreau triple sec to create the effect. Thankfully, mixologist gaz regans recipe from the joy of cocktails stays away from the vegetable aisle. It is tricky to find a decent blue curaao that isnt 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. If you dont have the blue stuff, you can use triple sec with a drop or two of blue food dye added just like the original.