Not too dissimilar from a whiskey sour (with egg whites of course), this cocktail also adds a hint of absinthe. Adding both aroma and just a hint of the distinctive absinthe flavor, the result is a pleasantly tart and aromatic sour that’s very easy to drink. Despite its caption in the book, I don’t recommend too many of these if you’re planning on spending anytime with rattlesnakes! ... Add all ingredients to a cocktail shaker with ice.