From David Lebovitz
Garnish: orange twist
Add all ingredients to a mixing glass filled two-thirds with ice and stir briskly for 15 seconds.
Strain into a chilled coupe glass.
Express an orange peel (colored side down), then drop into the glass.
The classic Jaguar cocktail uses green Chartreuse, but if you want something a little smoother, give it a go with yellow Chartreuse, which is mellower and a bit sweeter than green Chartreuse.