Place the cubed watermelon flesh into the blender jar. Blend on high speed until completely smooth and no large chunks remain, about 30 seconds. Observe the mixture turning bright pink and becoming liquid.
4 cups watermelon flesh, cubed
Set the fine-mesh strainer over a large mixing bowl. Pour the blended watermelon through the strainer, gently pressing with a spatula to extract as much juice as possible. Discard the pulp remaining in the strainer. The liquid should be clear and bright pink.
4 cups watermelon flesh, cubed
Roll the lemon on the countertop to loosen juices, then cut in half. Use a citrus juicer or reamer to extract 2 tablespoons of fresh lemon juice. Pour the juice into the strained watermelon liquid.
4 cups watermelon flesh, cubed
Add 0.5 cup of cold water to the watermelon and lemon mixture to dilute slightly, then stir well to combine. Adjust the amount of water to suit your desired consistency.
4 cups watermelon flesh, cubed
Pour the finished watermelon lemonade into chilled glasses, garnish with lemon slices if desired, and serve immediately to enjoy its refreshing, translucent appearance.
