The latest Cocktail Challenge, in which local bartenders challenge fellow bartenders with an ingredient of their choice.

Donnie Krause of Yusho is familiar with the intoxicating effects of Robitussin, the ingredient with which Matchbox bartender Graham Courter challenged him to create a cocktail. "Growing up in Joliet, I might have had some experiences with it in high school," he says.

He'd never before sat down with a bottle of the cough syrup to tease out its nuances, though. "What surprised me the most was that as assaulting as it is up front, the flavor that lingers is . . . reminiscent of chartreuse, herbs, spices." Krause capitalized on those flavors by creating a syrup using Robitussin, Bonal (an aperitif with a similar flavor profile), and molasses-y Okinawan black sugar. But matching the syrup to an appropriate spirit proved tricky.

"The Robitussin comes through pretty strong," Krause says. "Nothing could stand up to it. It just comes up front and beats the hell out of your palate." The answer turned out to be a Japanese whiskey: 12-year-old Nikka Taketsuru, which is smoky enough to combat the strong flavors of the cough syrup.

Krause created a play on a perfect Rob Roy: a cocktail that's like a manhattan, but made with scotch; "perfect" means that it's made with both dry and sweet vermouth. Krause says it's "smoky up front, a bit of dry sweetness, and finishes with the herbal, medicinal flavors of Robitussin."

He named the cocktail Roy San's Perfect Lean, "lean" being another term for a drink made with prescription-strength cough syrup that's swigged recreationally.

Peter Holderness

Roy San's Perfect Lean

Who's next: Krause has challenged Remy Walle of Gilt Bar to create a cocktail with umeboshi, or pickled ume, a Japanese fruit related to the apricot.

Roy San's Perfect Lean

.75 oz Robitussin syrup*

.5 oz Dolin dry vermouth

.5 oz Rabarbaro Zucca amaro

1.5 oz Nikka Taketsuru 12-year-old whiskey

Robitussin-soaked cherries (for garnish)

Add all ingredients except cherries to a mixing pitcher with ice and stir until chilled (about 15 seconds). Put two or three cherries that have been steeping in Robitussin for at least six days on a toothpick. Strain cocktail into a coupe glass and set the toothpick on the rim; set a piece of orange peel on fire and use it to flame the cherries.

*Robitussin syrup: Combine three parts Robitussin with one part Bonal and one part Okinawan black sugar and heat until the mixture is reduced slightly. Let cool