A bartender at Ireland’s Shannon Airport created this drink in the 40s to appeal to American tourists, and boy, it stuck.
The cream should be whipped until soft peaks form, and gently slid atop the drink. If you want to add some extra flavor, mix in a big pinch of sugar, some vanilla extract, or a splash of whiskey while you’re whipping.
Build everything but the whipping cream in the order given in a mug or heatproof coffee glass. Whip the cream until soft peaks form, and gently float it on top of the drink.