First make your watermelon syrup by combining the watermelon cubes, lime juice, honey and mint leaves in a small sauce pan. Then muddle the watermelon with the other ingredients and cook on medium-low heat until the ingredients are heated and combined.
Strain the syrup using a fine strainer into a jar. Place in the refrigerator for a least an hour (or freezer for 15 minutes if in a hurry) before using in cocktail.
Fill 2 chilled glass with crushed ice, then add 2 ounces of rum and 2 ounces of watermelon syrup to each glass. Top off with club soda and add a sprig of mint for garnish.
Recipe by Oakhurst Kitchen at http://oakhurstkitchen.com/watermelon-mojito-cocktail/