Crème de cassis is a sweet blackcurrant liqueur, intensely fruity and dark-berry-like with a slightly tart, tannic edge. It’s a “crème” style liqueur, meaning high sugar and viscosity.
It’s famous with sparkling wine (Kir Royale) and also works with gin or vodka when you want deep berry without relying on juice. Compared with raspberry liqueur, cassis is darker, more winey, and more concentrated.