Slightly sour, light, uncloying: those aren't words I'd normally use to describe a chocolate-based cocktail. But this drink, inspired by a shot of pure cacao pulp puree that I drank at a chocolate workshop here in New York, hits all of those notes. It's what I imagine a chocolate bar would taste like if it were somehow also a tropical fruit, and that's not an accident: cacao pulp is the "fruit" of the cacao plant, the succulent flesh that surrounds cocoa beans in the pod. It's a relatively under-the-radar ingredient, a byproduct of the standard chocolate-making process that needs to be removed before we can get at the beans that make up what we think of as chocolate. But its flavors are worth paying attention to, with notes reminiscent of lychee, pear, and melon.