Roughly chop mint leaves.
Puree the mint, blackberries, and sugar in a blender. Press through a fine sieve into a bowl; discard seeds.
Rinse blender, then return puree to blender, and add bourbon and small ice cubes; blend until smooth. Divide mixture among 4 glasses. Garnish each with a mint sprig
Like the original, our julep features bourbon infused with mint. But this drink's signature sweetness is tempered by the tartness of blackberries, which also tint it a gorgeous shade of purple. Another twist: Our cocktail is blended with -- rather than served over -- ice, creating a slushy texture