Begin by cubing 2 lbs of chilled, seedless watermelon, ensuring it's ripe for maximum sweetness. Place the cubed watermelon into a blender and blend until it becomes a smooth puree, roughly 2-3 minutes. Strain the puree through a fine mesh strainer into a bowl to separate the juice from any pulp.

In a large pitcher, add 4 cups of cold water, fresh strained lemon juice, and ¾ cup of granulated sugar. Using a whisk, combine these ingredients for 2-3 minutes until the sugar completely dissolves. Taste and adjust sweetness.

Pour the strained watermelon juice into the pitcher. Stir gently for another 1-2 minutes to ensure everything is fully combined.

Fill tall glasses with ice, pour the refreshing drink over the ice, and garnish each glass with a sprig of fresh mint.