01 - Place watermelon cubes, cucumber slices, mint leaves, and lime juice in a blender. Blend until completely smooth, approximately 30-45 seconds.
02 - Pour blended mixture through a fine mesh sieve into a pitcher, pressing with a spoon to extract liquid. This step removes pulp for a smoother texture.
03 - Stir in erythritol or preferred low-carb sweetener until fully dissolved. Taste and adjust sweetness level if needed.
04 - Pour cold sparkling water into the pitcher, stirring gently to combine while maintaining carbonation.
05 - Pour into glasses filled with ice cubes. Garnish with additional mint leaves and a lime wedge if desired. Serve immediately while chilled.