Holeman & Finch Public House · AtlantaGreg Best named this Irish whiskey–based cocktail after Oisín, a mythological Celtic warrior. Oisín's mother, in some versions of the story, was turned into a deer after he was born. More Whiskey Cocktails
Fill a cocktail shaker with ice. Add all of the remaining ingredients except the cinnamon and shake well. Strain into an ice-filled rocks glass and garnish with the cinnamon.