fresh pineapple chunks
fresh mint leaves, plus a sprig for garnish
fresh lime juice, plus a wedge for garnish
- For simple syrup: Put sugar and 2 teaspoons water in a glass bowl and microwave on full power for 10 to 15 seconds, or until sugar is dissolved.
- Drop blackberries, pineapple, and mint leaves into a sturdy glass and crush to a pulp with the end of a wooden spoon.
- Add the simple syrup, lime juice, and rum.
- Pour the contents into an old-fashioned glass and then back into first glass; repeat until thoroughly mixed, then pour back into old-fashioned glass.
- Add ice cubes and seltzer; stir.
- Garnish with sprig of mint and lime wedge.