Here's how to do it:

Equipment: Cocktail shaker, strainer

Ingredients: 2oz gin, ½ oz Green Chartreuse, 1/2oz lime juice

Do this for 1 drink:

Fill a cocktail shaker with ice. Add gin, Chartreuse, and lime juice. Shake until well chilled, about 15 seconds. Strain into cocktail glass and serve.

Adapted from a recipe here.