A little bit of sweetened heavy cream poured over a very tart granita.
It's one of those things that magically turns out to be far more than the sum of its parts. The granita is all crunchy crystals, but the cream settles around them and refreezes, softening the edges, while still maintaining the essential structure. And it tastes pretty fantastic.
You start by making a granita out of whatever juice you like. I've only tried it with the kind of thick, tart juices I wouldn't want to drink straight — black cherry, concord grape, some kind of blueberry/pomegranate concoction — but I bet something more mellow, like pear, would be good too. There are nice step-by-step directions here, though I don't add extra sugar to the juice. When it's frozen and you're ready to eat, pour a couple of tablespoons of heavy cream into a ramekin, add a teaspoon or so of sugar, and stir until the sugar dissolves. This should also thicken the cream a bit, though not to the point that it'll hold peaks. Pile some granita into a little dessert cup, pour the cream on top and give it a minute to merge. Magic.