Stir ingredients with ice, strain into glass with large rock or sphere. Twist grapefruit peel over drink and garnish.
Also works with orange twist. Tanqueray 10 was in one of the Negroni dell'Etna recipes and would be worth a try, so I used a few drops of lime juice in my initial version with standard Tanqueray. Hayman's London Dry might work well too.
This recipe was a happy accident as I intended to make a Negroni dell'Etna, but had Erborista stuck in my brain and made the inadvertent substitution. Since this is a variation, I simply altered the name to match. The Erborista introduces a pipe tobacco/sandalwood aroma and umami. While bitter up front from the Campari and the pine terpenes of the Erborista, it transitions to a Zucca rhubarb-like umami, before finishing with a robust bitterness. The result is an added dimension to the Negroni template.