Bijou means “Jewel” in French, and the reason this cocktail is called Bijou is because it combines all the colors of the three most precious jewels in the world: diamond (gin), ruby (vermouth), and emerald (chartreuse). The real Bijou is supposed to made Pousse-cafe style, so the colors are not mixed and the colors of all the jewels are beautiful and defined, which look like “jewels”, hence the name Bijou. Nowadays, Bijou cocktails are served with the ingredients all mixed together, which is called a completely different name: Amber Dream, for the color it shows.
Serve straight up without ice in a cocktail glass
3 parts gin
1 part green chartreuse
1 part sweet vermouth
Dash orange bitters
Stir in a mixing glass with ice and strain
Garnish with a cherry
Chris Palmer from San Diego [CC BY-SA 2.0], via Wikimedia Commons