When Greg Lindgren and Jon Gasparini first opened up Rye Bar, the pair researched all the possible ways to use rye whiskey in cocktails, but it was the lost classic American liqueur "rock and rye" that really piqued their interest. This combination of cinnamon, clove, fresh and dried citrus peels, and the medicinal herb horehound, steeped in rye and sweetened with rock candy, was a popular remedy for colds in the early 1900s.
After some experimentation -- and some unpleasantly astringent and powerful batches due to the oversteeping of the horehound -- Lindgren perfected the recipe by using horehound candy in place of the herb and to sweeten the mix. Originally designed to go into a Rock & Rye Hot Toddy ($10, rock and rye liqueur, hot water, cinnamon stick, citrus), the spiced liqueur also works cold in the Rock & Rye Old Fashioned ($10), which is simply the liqueur, chilled with bitters.
The mix isn't always the same, as Lindgren and Gasparini encourage the bar staff to add their own flourishes when replenishing the infusion at the end of the night, meaning that it can get more spice in the winter and fruit in the summer.
On a recent cold and foggy night, I wasn't sure I could feel the purported curative effects of the horehound in the toddy, but the warmth certainly clung all the way home.
Rye Bar, 688 Geary (at Leavenworth), 474-4448