01 - Place the watermelon cubes in a blender and blend until completely smooth, forming a vibrant puree.
02 - Pour the watermelon puree through a fine mesh sieve into a large pitcher to remove excess pulp for a smoother texture. This step is optional.
03 - Add the freshly squeezed lemon juice and sugar or agave syrup to the pitcher. Stir vigorously until the sweetener completely dissolves.
04 - Pour in the cold water and mix thoroughly. Taste the mixture and adjust sweetness or acidity levels according to personal preference.
05 - Refrigerate the lemonade for at least 1 hour to allow flavors to meld, or serve immediately over ice cubes for instant refreshment.
06 - Finish by garnishing individual glasses with fresh lemon slices and mint sprigs just before serving for a polished presentation.