Preheat oven to 180C on fan force setting.
Grease pudding dish with butter, add a 1/2 cup of passionfruit purée to base of the dish and set aside.
Mix melted butter, sugar and egg yolks in a bowl, stirring as you go to create a smooth batter.
Add remainder of passionfruit purée, along with the flour and mix again until smooth and all the ingredients are combined.
Whisk egg whites to the soft peak stage. Gently fold the passionfruit batter through the egg whites a little at a time, mixing lightly to keep as much volume in the batter as possible.
Spoon batter into the pudding dish over the passionfruit puree and smooth batter out gently with the back of a spoon.
Bake pudding in the oven for 25mins, until pudding is golden on top.
Dust with icing sugar and serve pudding whilst warm with a dollop of creme fraiche. (Optional) serve additional passionfruit purée on the side.