Preheat the oven to 180C/365F/Gas 4.
Place the butter and sugar into a large bowl and mix together well, until light and fluffy.
Add the flour, milk, egg yolks and half of the passion fruit pulp, and stir until just combined.
Whisk the egg whites in a clean bowl until stiff peaks form when the whisk is removed.
Fold the egg whites into the passion fruit mixture.
Divide the cake mixture among four greased and floured 6fl oz/170ml ramekins or dariole moulds and place onto a baking tray.
Transfer to the oven and bake for 12 minutes, or until cooked through.
Meanwhile, for the sauce, place the sugar and water into a pan over a medium heat and bring to the boil. Reduce the heat and simmer for 15 minutes, until thickened to a syrup, then remove from the heat.
Add the remaining passion fruit pulp and the coconut liqueur and stir well.
To serve, place the puddings in their dishes onto plates, drizzle the sauce over the top of each and top with a dollop of whipped cream.