We stumbled on this cheeky number from the out-of-print playboys host & bar book in punch magazines coverage of the book. We had been looking for some new wine cocktails to test, and the double derby was a fortuitous find The double derby is sort of a riff on sangria, with juice and cassis syrup taking the place of sangrias fresh fruit. The original recipe calls for redcurrant syrup, which is a fairly rare ingredient (in the us, at least). Cassis syrup or liqueur works just fine in its place. The recipe works well as a punch, but its quite strong you can water it down by up to a quarter of its total volume, to replicate the effect of shaking with ice.