Preheat oven to 160C.
To make syrup,place passionfruit pulp,water and sugar in a small saucepan over a medium heat and stir until sugar is dissolved. Bring to the boil,reduce heat to low and cook for 10-15 minutes or until syrupy.
To make cake,place butter and sugar in the bowl of an electric mixer and beat for 10-15 minutes or until pale and creamy. Add vanilla,then eggs one at a time,beating well after each addition. Add yoghurt and beat until combined. Fold through the flour.
Spoon the mixture into a 22cm spring-form cake tin lined with baking paper and bake for 50 minutes or until cooked when tested with a skewer.
For the salsa,combine all the ingredients in a bowl and toss to combine.
Remove cake from tin,place on a serving plate. Pierce cake evenly with a metal skewer,and drizzle generously with the warm syrup.
Cover with mango salsa and extra passionfruit syrup,if desired.
Tip: For something a little quirky,cut the passionfruit syrup cake into small cubes,and arrange in a martini glass with a good drizzle of the passionfruit syrup and a generous spoonful of the mango salsa.