The insanely good gin & tonic from chaim dauermann at new yorks up & up bar is exactly what it says on the tin and so humble, too The secret ingredient is suze, a gentian-forward yellow herbal liqueur that used to be impossible to find in the us, but is beginning to show up at fancier liquor stores. If you cant find suze, strega or even yellow chartreuse make fine substitutes. Dauermann makes his own house lime cordial with fresh limes and peruvian pisco, but you neednt go to all that trouble. A well-made brand like bg reynolds will do you well; just avoid the corn syrup swill that is roses lime cordial.