Make simple syrup. In a small saucepan combine sugar, water, cranberries and mint and simmer, uncovered, until cranberries pop and release their color and flavor, about 5 minutes. Strain into a glass jar and cool to room temperature then refrigerate until ready to use up to 7 days.
¼ cup cranberries, ½ cup granulated sugar, ½ cup water, 2 tablespoons fresh mint leaves
In a cocktail shaker filled with ice add vodka, cranberry juice, lime juice and cranberry simple syrup. Shake to chill.