This is an old recipe usually credited to Leo Engels, an American bartender (working in London) who published the recipe in 1978 (recipe number 192 by the way) in his cocktail book, American and Other Drinks. The recipe bears a resemblance to the modern Sidecar, but with one significant difference. Mr. Engels used Angostura Bitters in the recipe (with the lemon juice and orange Curacao), lots of Angostura Bitters.
His recipe can be summarized as follows:
half a wine glass of brandy (about 1 3/4 oz)
2 teaspoons Orange Curacao
1 teaspoon Angostura bitters
1 teaspoon white sugar
1 teaspoon lemon juice
Shake well over fine (crushed ) ice
Strain into a wine glass
I have seen a few modern versions of the recipe, usually with the bitters toned down and the teaspoon of sugar replaced with a teaspoon of simple syrup. However, I recommend the original construction as well as the use of a robust brandy which will stand up to the bitters.
In the photo above I used Miguel Torres 20 Hors d’âge Brandy (see review here), which with its strong oak flavour running throughout works very well with the heavy dose of bitters. I also used the Pierre Ferrand Dry Curacao (see review here) to obtain as close to an original 1878 Curacao flavour as possible. Do not skimp on the sugar, as the lemon juice and bitters are unforgiving if not balanced by the appropriate amount of sweetness.