Stir with ice, strain into cocktail glass, garnish with lemon twist.
Ferro China Bisleri is the star of this cocktail. It is an amaro (bitter) that is notable for the presence of iron citrate (ferro in the name) as well as traditional quinquina. For decades in Italy this liqueur was widely promoted and used as a tonic for anemia and other ailments.
Ferro China has a broader pleasant amaro character than one would imagine, but accompanied by an intriguing metallic/rust flavor. Consumed neat, it presents the flavor and aftertaste of holding a penny or nail in the mouth. In a cocktail like this one, the effect is more subdued, while positively contributing.
I have used Hamilton 86 as the rum as well as El Dorado 3 yr. The darker rum broadens the palate more at the cost of pushing the ferro somewhat into the background. Adjust the rum quantity and type to tweak the ferro presentation. For vermouth I used Cocchi di Torino and Dolin Dry.
A Haiti cocktail is listed in the 1929 "L'Heure du Cocktail" but is completely different with gin, Byrrh and cassis. Grassi's 1936 collection of cocktails has his own version (slightly modified here) with him as the source among contributors.
Grassi's recipe is: 20% Vermouth Torino, 10% Campari, 30% Ferro China Bisleri, 10% Rhum Demerara, 30% Dry Vermouth, 2 dashes Angostura. Served with a lemon peel. He specifies shaken.
I have lightly altered the recipe based on a few tests comparing to the 1936 recipe. I recommend stirring rather than shaking and upping the rum proportion as in my posted quantities.