There are really no brandies made from blackberry juice. The flavor come from natural or artificial additives in a brandy or sugary liqueur. You can use these store bought versions; I made my own blackberry brandy by cooking a blackberry syrup and adding it to cognac. It's pretty smooth and fruity, and it is at least made from real stuff.
- 2 oz. light rum
- 1/2 oz. blackberry brandy
- pineapple juice