How to Make It
Muddle mint leaves, sugar cubes, cucumber slices, and grated lemongrass in a cocktail shaker. Add fresh-pressed cucumber juice, white rum, and fresh lime juice. Swirl to combine. Add ice, cover with lid, and shake vigorously until thoroughly chilled. Strain into an ice-filled Collins glass. Top with club soda. Garnish with cucumber slices and mint leaves, if desired.