Directions

1. Combine blackberries, sugar syrup, and lime juice in a cocktail shaker. Muddle the blackberry mixture until blackberries are crushed and juicy.
   

2. Add ice and shake vigorously to combine juices with other ingredients.
   

3. Strain into a glass filled with fresh ice cubes or cracked iced. Stir in Guinness and garnish with a lime wedge.