Arnaud's Special was the house cocktail of the famous Arnaud's Restaurant of New Orleans in the 1940's and 1950's. It's a Southern take on a Rob Roy where the sweet vermouth and Angostura Bitters are replaced with the Dubonnet and orange bitters.
If you're looking for a dry cocktail give this a try. It's a great cocktail to sip before dinner. Just make sure you use the new Dubonnet released in the States last year, it's more like the original 1846 formula and the Dubonnet that Europe has always had access to. Even though Arnaud's most likely used the first American version, this new Dubonnet is much more complex and makes this cocktail way more interesting. (FYI, during the 1940s, when Hitler had control of France, the United States could not import Dubonnet so a different version was created in the U.S. It was, however, milder and less bitter as a result of the reduction of the quinine.)