Build the base

• Pour the fresh watermelon juice, lemon juice and bourbon into a tall glass.
• Add the lemongrass simple syrup and stir briefly to combine.

Add ice and stir

• Fill the glass to the top with ice.
• Lift from the bottom with a bar spoon to incorporate the ingredients.

Top with bubbles

• Pour the chilled prosecco down the stem of the spoon to keep the carbonation, stopping just before the top.
• Lift once more, then finish with a splash of club soda.