In a medium pitcher, combine the orange juice, simple syrup and basil. Use a wooden spoon or a muddler to crush the basil leaves in the bottom of the pitcher. Stir in the rum and club soda. Serve immediately in individual glasses over crushed ice. Garnish with orange slices and fresh basil.

To prepare thick simple syrup, in a small saucepan, bring 1/2 cup water and 1/2 cup granulated white sugar to a boil. Reduce the heat to low and simmer, stirring the mixture until the sugar has dissolved. Remove the pan from heat and let cool.