Cherries in syrup blended whole with lime juice, water and ice. One step, five minutes, six glasses, and the syrup from the jar is doing the sweetening.
Three ounces of vodka turns this into a cocktail, which is what the original recipe suggested at the end. It is not in the ingredient list, so buy it separately if that is what you want. The cherries go in with their syrup and that is where most of the sweetness comes from. Taste before adding sugar: a jar of cherries in heavy syrup may need none at all, and eight ounces of lime juice needs something to balance it. Blend the ice in with everything rather than adding it to the glass. That is what gives this its texture, halfway between a lemonade and a slush, and it is why the recipe puts it in the blender. It also means it has to be drunk straight away.