I tried twice to bake this cake with passion fruit puree mixed into the batter and on both occasions I found the resulting cake to be on the dry side. Serving up dry cake is a kitchen crime I won't knowingly commit, so I opted to make vanilla sponges in this passion cake and add in the flavour of the fruit by way of topping them with a passion fruit syrup once baked and including plenty of passion fruit curd between the layers of cake and on top.