I don't know why but I wanted to think that this was going to be too sweet. Maybe it's the Cassis, maybe it's that I'm not a fan of Campari, but nonetheless I loved it. The rye I used (Bulleit) stood up to the Campari and subdued it so it merely acted as a balancing component to the cassis and rye, resulting in a boozy cocktail that could be served as both a digestif and an aperitif (maybe if you upped the Campari just a tad, or added some Aperol).
Another excellent drink. I was hesitant about the 3 drops of saline but it works well given the bitter element from the Campari. Difford's suggestion for the "original" Fogerty cocktail (using De Kuyper 'Dutch Cacao' Creme de Cacao instead of Crème de cassis) of serving on-the-rocks if one finds it too spiritous / bitter even with the saline, would work equally well here.
Made this with Wild Turkey 101 Rye, Campari, DeKuyper (US) Creme De Cassis, Orange Bitters by Angostura. Not as sweet as I expected (First time using the DeKuyper (US) Creme De Cassis; I couldn't easily find a better quality brand...).. At first, I was a little undecided on this, but it ended up being pretty sippable, as Difford's review claims... Sweet, subtle blackcurrant up front, fading into the rye whiskey, then the bitter orange of the Campari. The orange zest twist is an appreciated addition to the mix.
Interesting play of Spice(Rye), sweet(rye and Cassis) and Bitter (Compari). Rye is the king here so chose wisely. Might play with ratios a little and swap the bitters.