1 packet organic stevia (no after taste in my opinion) or1 oz Simple Syrup (optional if watermelon is super sweet) (Mix equal amounts water and sugar in saucepan and boil just until sugar is dissolved. Cool)
3 ounces light rum
Chilled club soda
2 mint sprigs
Combine watermelon, mint leaves and lime juice in a cocktail shaker and muddle until leaves are broken up slightly and watermelon is crushed.
Fill shaker with ice, add the simple syrup and rum.
Shake until ice cold.
Fill glasses half full with ice; pour contents of shaker (do not strain) including ice into glasses.