In some ways, the freezer Alaska at Le Rock is like any other: gin, Chartreuse and dilution, poured straight from the bottle into a petite V-shaped glass. But at the Rockefeller Center restaurant, where the L’Alaska appears on the bar’s Martinis Maison menu, the dilution holds a secret. Inspired by the tisane blend taken as a bedtime drink by the Carthusian monks—makers of Chartreuse—beverage director Estelle Bossy creates her own cold infusion of mint, lemon verbena, linden and orange flower to lengthen the cocktail while boosting its herbal complexity. Paired with the distinctive botanical profile of Monkey 47 gin and a finishing spray of the potent Chartreuse Élixir Végétal, the drink has a freshness and depth of flavor that set it apart from the very first sip. It’s been nearly a month since I last tried it and I still can’t stop thinking about it. I plan to make a batch at home to treat as my very own bedtime tisane, and you should too.