Pineapple and arugula aren't really flavors I've ever thought of combining, never mind in a daiquiri. But I was more than convinced otherwise when I tried it at SY Kitchen on my recent day trip to Santa Ynez and now it's my go-to unexpected drink I shake up for company.
Place pineapple in a blender or food processor and process until smooth. Place arugula in a cocktail shaker with simple syrup and lime juice and muddle until arugula is broken up. Add pineapple puree, rum, and ice. Close and shake until cold to the touch. Strain into a chilled cocktail glass, top with a few drops of bitters, then drag a toothpick through the bitters to make a heart shape and serve.
Puree can be made up to 1 day in advance.