This classic cocktail dates back to 1937 and is named not for the time period, but for the stylish 20th Century Limited train from New York to Chicago. It’s a perfect example of how an aperitif (Lillet) and a liqueur (crème de cacao) can combine to lift a cocktail above the ordinary.
• 1.5 oz (45 mL) gin
• 0.75 oz (22 mL) Lillet Blanc
• 0.5 oz (15 mL) light crème de cacao
• 0.75 oz (22 mL) lemon juice
Place all ingredients in a cocktail shaker with ice. Shake well, then fine-strain into a chilled cocktail glass. Garnish with a twist of lemon peel. Serves 1.