1.
Cut the passion fruits in half and scoop out all the pulp. Set the shells aside.
2.
Mix the pulp, egg yolks, sugar, cornflour and salt in a cold saucepan.
3.
Place the pan on the stove and heat the mixture slowly while stirring constantly until it thickens.
4.
As soon as the mixture has thickened and is hot, remove from the heat and stir in the cold butter.
5.
Let cool slightly, then stir in the crème fraîche.
6.
Carefully fill the passion fruit shells.
7.
Chill for at least 2 hours before serving.