Be careful not to use too much mint leaf in step 1 or your smoothie will turn brown in color. Still good, but not as pretty.
When watermelon is frozen you are ready to prepare the smoothie. In a blender process ginger ale and just 1 mint leaf for about 15 seconds. If you use too much green mint leaf your smoothie will turn brown in color.
Add watermelon cubes and lime juice and process until slushy. Pour into chilled glasses and garnish with remaining mint leaves. Serve immediately.
You can double or triple this recipe.
Note: You can freeze a large batch of watermelon cubes and save in a zip lock bag to make this whenever you desire.