01 - Place watermelon cubes in blender and process until completely smooth.
02 - Pour watermelon puree through fine mesh sieve into large pitcher to remove pulp, if desired.
03 - Add freshly squeezed lemon juice and sugar or agave syrup to pitcher. Stir vigorously until sweetener fully dissolves.
04 - Pour in cold water and mix thoroughly. Taste and adjust sweetness or acidity levels as needed.
05 - Refrigerate for minimum 1 hour to develop flavors, or serve immediately over ice.
06 - Decorate glasses with fresh lemon slices and mint sprigs before serving.