This drink comes from the PDT Cocktail Book, as a variation on the Chancellor cocktail from Esquire. I swapped around the exact varieties of spirits to suit what I had on hand, but I think it turned out reasonably well.
2 oz aged rhum agricole
0.75 oz tawny port
0.5 oz sweet vermouth
1 dash Angostura bitters
1 dash orange bitters
Combine all ingredients, stir with ice for fifteen seconds, then strain into a chilled cocktail glass.
The nose is dominated by the rhum, though inflected with sweet grape notes from the port and vermouth. The sip begins with very mild sweetness, which grows a bit towards mid-palate. Further back there's a complex interplay of various bitter notes and grape/brandy flavors. The finish is mostly bitter, between the vermouth and bitters, with just a bit of vanilla.
This is a really interesting drink to me because it's highlighting rhum agricole in a cocktail that's not a tiki drink. Sort of like scotch, it can be a difficult ingredient to work with because it doesn't always play well with others. However, using a more mellow VSOP rhum will probably come out smoother than the more fiery Rhum J.M. ESB that I picked. Either way, I think this is a really nice twist on the standard Manhattan mold.