Begin by cutting your chilled seedless watermelon into cubes. Use about 4 cups of watermelon, placing them into a blender. Blend on high until smooth, which should take about 30 seconds. Once blended, pour the mixture through a fine mesh strainer into a bowl, pressing gently with a spatula to extract as much juice as possible while discarding the pulp.

In a large pitcher, add 2 cups of cold water, freshly squeezed lemon juice, and granulated sugar. Using a whisk, mix these ingredients thoroughly for about 1-2 minutes until the sugar completely dissolves. Taste the mixture and adjust the sweetness if needed.

Carefully pour the strained watermelon juice into the pitcher containing your lemonade base. Stir gently with a spoon until everything is well combined. The mixture should have a vibrant pink color.

Fill individual glasses or a large serving pitcher with ice cubes to keep the Watermelon Lemonade extra cool. Pour the lemonade mixture over the ice, filling each glass to the brim. Garnish with a sprig of fresh mint.

If not serving immediately, cover the pitcher and store in the refrigerator for up to 3 days. Stir gently before serving.