In Corpus Christi, Texas, distiller Nathan Bitz has pulled off an unusual creative coup: researching and producing his own version of the fabled liqueur Chartreuse, whose notoriously top-secret recipe is reportedly known only to the two monks responsible for its distillation. Named Génépi, after the Chartreuse family of liqueurs, this Texan chartreuse is now being sold and mixed into cocktails at Bitz’s Aerodrome Distilling. A former navy helicopter pilot, Bitz’s love for Chartreuse began when he discovered the Last Word, a forgotten Prohibition-era cocktail that features the monks’ “elixir of…