STIR all ingredients with ice and strain into chilled glass.
Lemon zest twist
Orange always works when mixed with cognac and here Dubonnet also tames and adds an aromatic wine complexity.
This cocktail is named after Barney Barnato, who was born Barnett Issacs in 1852 in the Whitechapel slum of London and traded on his Jewish-Cockney wit and humour. With only a box of cigars to his name, in 1873 Barney fled poverty to join his brother in the South African diamond rush and changed his name. He formed the Barnato Diamond Mining Company and within ten years he had become a millionaire. He and his brother were eventually forced to sell out to Cecil John Rhodes for $5,338,650, then the single largest cheque that had been written. The fortune was little compensation for being beaten in the battle to control the Cape diamond mines - Rhodes went on to form the now mighty De Beers.
After a brief spell in South African politics Barnato died in 1897 when he was lost overboard near the island of Madeira, whilst on a passage home to England. It is still questioned as to whether he jumped, fell or was pushed. His body was recovered but the mysterious circumstances of his death were never resolved. He is buried at Willesden Jewish Cemetery, London.
His vast fortune was divided between his family, including his sister Sarah and her husband Abraham Rantzen, great-grandparents of English TV presenter Esther Rantzen. Another beneficiary was his son, Woolf Barnato, who used part of this inheritance to become one of the so-called Bentley Boys racing drivers in the 1920s.
This recipe is adapted from Harry Craddock's 1930 The Savoy Cocktail Book which calls for a now defunct South African product called Caperitif. We have used Dubonnet Red in its place, but some consider white vermouth or aromatised wine a better substitute.