Blend the Ingredients: Begin by cubing ripe watermelon and placing it into a blender. Add a handful of fresh mint leaves and the juice of one lime. Blend on high for about 30 seconds until smooth.

Strain the Mixture: Pour the blended watermelon mixture through a fine mesh sieve to filter out the pulp, pressing down with a spatula.

Prepare the Glasses: Fill each glass with ice cubes to chill before serving.

Combine with Sparkling Water: Pour the strained watermelon mixture into each glass and top with a splash of sparkling water.

Garnish and Serve: Garnish with a sprig of mint and, if desired, a lime wedge.