Melt the Nutella in a bain-marie or in a bowl over a pan of simmering water.
Break the eggs and separate the whites from the yolks. Sieve the cornflour into a bowl and mix with 60g of the sugar.
Add the egg yolks, two at a time, to the melted Nutella, followed by the vanilla sugar and finally the cornflour and sugar mixture.
Preheat the oven to 220C. Beat the egg whites until they form stiff peaks then fold in 50g of the sugar. Carefully fold the beaten egg whites into the Nutella mixture but do not work them together too much.
Grease 6 moulds or small soufflé dishes and dust with the remaining sugar. Pour the mixture into the dishes and bake for 25–30 minutes.
Remove from the oven, sprinkle the soufflés with icing sugar and serve.