Put the pineapple juice, rum, lime juice, Demerara Sugar Simple Syrup and 1 sprig rosemary in a mixing tin and lightly muddle the rosemary. Add ice, shake vigorously and strain into a glass over fresh ice. Garnish with the remaining rosemary sprig and a lime wedge.
Demerara Sugar Simple Syrup:
Combine the sugar and 1/2 cup water in a pot over medium-high heat and bring to a boil. Lower the heat to medium and simmer until the sugar dissolves. Let cool completely.