It’s always a surprise when big, herbal liqueurs like Green Chartreuse meld so well with citrus ingredients, but the Last Word is just a terrific cocktail.
The lesson to take from this drink is that you can basically mix gin with a small amount of any sweet or semi-sweet liqueur, and your odds of having a quality drink at the end of it are pretty good.
The key is the orange peel: you need a hefty chunk of it, it needs to be as pith-free as possible, and you need to muddle the heck out of it to really get those essential oils out and into the drink.