This calls for a cognac with a spicy-woody profile; I used Braastad XO. Following J. Guerrero I used 1/4 oz ginger syrup instead of plain sugar syrup. Experimented with Bittermens Elemakule Tiki Bitters instead of Angostura and garnished with lime zest and slice of pickled ginger. Agree this is more interesting and flavorful than the Moscow Mule.
Better than a Moscow Mule, the Cognac works with the ginger. I usually add less sugar syrup for cocktails, but this amount worked well, but that depends on how sweet you ginger beer is.