Four ingredients — milk, light rum, lime juice, and a 7.6-oz pouch of blueberry-pomegranate frozen smoothie mix — go straight into the blender for a thick frozen cocktail that's ready in 5 minutes. The yogurt chips in the smoothie mix give it body without adding separate dairy. A tablespoon of lime juice keeps the sweetness in check. Serves two; pour into chilled glasses and drink right away before the slush softens.