01 - Add cubed watermelon to blender and process until completely smooth, approximately 30-45 seconds.
02 - Pour watermelon puree through fine mesh sieve into large pitcher, pressing with spoon to extract juice and remove fibrous pulp. Discard pulp or reserve for another use.
03 - Add fresh lemon juice and sweetener to pitcher. Stir vigorously for 1-2 minutes until sweetener fully dissolves.
04 - Pour in cold water and mix thoroughly. Taste beverage and adjust sweetness with additional sweetener or acidity with more lemon juice as desired.
05 - Refrigerate for minimum 1 hour to allow flavors to meld, or serve immediately over ice. Garnish glasses with lemon slices and fresh mint sprigs before serving.