On paper, Penicillin(scotch) or the Gold Rush (bourbon) is a very simple drink. Composed of bourbon, honey syrup and fresh lemon juice, it’s essentially a Whiskey Sour with honey in place of sugar. This also essentially makes it a variation on the classic Bee’s Knees cocktail, but one that uses bourbon rather than gin. The interplay of whiskey and honey transforms the cocktail’s flavor and mouthfeel, making the Gold Rush a drink that transcends the sum of its parts. The Gold Rush was first created at famed New York City bar Milk & Honey in the early 2000s, and became a staple of bars worldwide at such a pace that the cocktail is often commonly assumed to have been a pre-Prohibition classic, rather than a modern drink. But its appearance came at a time when new drinks were appearing all over the U.S. fueled by a new generation of craft bartenders experimenting with tweaks to classic cocktails. Newly available liqueurs were poured liberally, alternate base spirits were swapped into tried-and-true recipes, and rules were broken with regularity.