1. Muddle the lime wedges and mint in the bottom of a cocktail shaker. Then add the blackberry syrup, lime juice, and rum

2. Fill the shaker with ice, cover, and shake vigorously for 15 seconds until the drink is nice and cold.

3. Strain the cocktail mixture into 2 tall glasses filled with ice, then fill the glasses the rest of the way with soda water.

4. Garnish with fresh mint, lime wedges, and or fresh blackberries.