Watermelon Basil Bliss

Using a large wooden spoon, chop the basil leaves and stalks with the sugar in a medium bowl. Pour in the lime juice and stir until the sugar is dissolved.Using portions, chop the watermelon cubes in a blender or food processor until smooth. Using a rubber spatula, squeeze the watermelon juice through a fine-mesh sieve and into a jug. Avoid the watermelon pulp.Pour the remaining basil syrup through the same fine-mesh sieve into the watermelon juice. Remove the leaves and stems. Add the vodka to the juice mixture and mix until smooth.Fill 8 large glasses with ice, pour the mixture, and serve immediately. If desired, garnish with watermelon slices and basil leaves.