1. Begin by blending the watermelon cubes in a blender until smooth. This should take about 1-2 minutes, ensuring there are no chunks left.
2. Using a fine-mesh sieve, strain the watermelon puree into a large jug to remove the pulp. This step is crucial for achieving a smooth consistency.
3. Add the fresh lime juice and mint leaves to the watermelon juice. Gently muddle the mint leaves with a wooden spoon to release their aroma.
4. If you prefer a sweeter drink, stir in honey or agave syrup until thoroughly mixed.
5. Just before serving, add the sparkling water to the jug and stir gently to combine.
6. Fill glasses with ice cubes and pour the watermelon mocktail over the top.
7. Garnish each glass with a sprig of mint and a slice of lime for an extra touch of elegance.

One of my favorite parts of making this drink is watching the vibrant pink hue come to life in the glass. It reminds me of painting with my daughters, each stroke bringing a new flavor to the canvas.