I’m a big fan of this cocktail. While hosting guests I did a variation with Lairds BIB Apple Brandy and it was a hit. I did a 50/50 split of Lairds to Ferrand 10 Generations Cognac.
Did not try this cocktail (don't have Champagne), but this was actually created in essentially the same way by Kevin Kos back in December 2021. The idea of a Sidecar with sparkling wine was probably even older than the 2020s, too.
Wow, it really is old. There probably are so many cocktails which were made decades ago, but never saw the light of day, only for a bartender decades later to claim it as the original. As always, thanks for everything you do Simon, and thanks for your input, Ian.
Orange zest and twist added a lot. Must try.