The Cloister is a cocktail with gin, grapefruit juice, lemon juice, and chartreuse. The cocktail first appeared in 1971 in the Playboy Bartender’s Guide. The monastic name comes from the use of the yellow Chartreuse, the complex herbal liqueur made by the Carthusian monks, in France.
Combine all ingredients in a mixing tin and shake with ice.
Strain into a chilled coupe.
Garnish with grapefruit twist.