For the curious, the Chartreuse liquor isn't the original formula, it was developed in the late 1800's, IIRC.

The original "secret elixir of eternal youth" from the crusades era is still available though, it's meant to be consumed as a medicinal tonic with a spoon. It comes in a cool small wooden bottle, I just scored and got three of them at my local Total Wine [3].

Edit: I just realized most probably aren't familiar with the history here. It's a fascinating story that starts with the crusades, involves the monks feeling both France and Spain, smuggling the recipe through prison, etc... [1] [2]

[1] https://www.chartreuse.fr/en/story/

[2] https://en.wikipedia.org/wiki/Chartreuse_(liqueur)

[3] https://www.totalwine.com/spirits/liqueurscordialsschnapps/h...