Place the sugar and 1/2 cup water in a small pot and bring to a boil. Once the sugar has dissolved, remove from the heat and add the basil stems. Allow the basil to infuse the simple syrup for approximately half an hour.
Remove the basil stems and strain the basil syrup into a bowl. Add the passion fruit pulp to the syrup, stir to incorporate and set aside.
In a chilled metal bowl, place the whipping cream, cream cheese, vanilla and sugar. Whip until medium-soft peaks form.
To assemble, place a shortcake on a serving plate. Spoon the passion fruit basil syrup over and around the cake. Dollop the chantilly cream on the cake and garnish with a reserved basil leaf.