The Penicillin is a modern cocktail and the first one I know of to combine scotch, lemon, honey, and ginger; a flavor combination that has since been used in several other drinks. It also calls for a small float of smoky scotch on top of the drink, a flavor trend that is currently quite popular in top cocktail bars.
Smoky drinks get their flavor from Islay scotch, mezcal, or other smoked ingredients including syrups, bitters, and even smoked ice!
The drink was created by Sam Ross, a bartender at New York's Milk & Honey bar, but I've had it in several other bars around the US and in the UK. Good drinks get around.
Adapted from Sam Ross of Milk & Honey
2 fl. oz. Blended Scotch (such as Famous Grouse)
.75 fl. oz. Fresh Lemon Juice
.75 fl. oz. Honey Syrup (3 parts honey to 1 parts hot water)
.25 fl. oz. Islay Scotch (such as Laphroaig)
1 1-inch long piece of Peeled Ginger
Muddle the ginger in the bottom of a cocktail shaker to break it up and release the juice. Add blended scotch, lemon juice, and syrup, fill with ice and shake well. Strain into an ice-filled rocks glass and float Islay scotch on top.