As Biggie-Smalls said, “Where Brooklyn At?! Where Brooklyn At?!” If you’re looking for the Brooklyn cocktail, it’s right here, but this drink could easily have been lost and forgotten. Unfortunately, this drink was never as popular as its’ other New York cocktail buddies, the Manhattan or Bronx, and once prohibition came along, history mostly forgot about the Brooklyn.
The main reason people probably stopped making it is one of the main ingredients, Amer Picon, stopped being imported into the United States a long time ago. It is still manufactured but can only be purchased in Europe. Amer Picon is a kind of an herbaly, orangy, bitter/sweetish digestive bitter. I really wanted to include this cocktail so in place of Amer Picon you can try using Amaro Nonino. At about 50 clams a bottle so it’s pretty pricy but at least it can be purchased.
As a side note, if you live outside the USA, then none of this substitution stuff matters, but I think around 80-85% of my users live in the US, so that’s the audience I try to write a bit more to.