Break the eggs by separating the white from the yolks in 2 bowls.
Add the mascarpone and vanilla sugar to the egg yolks.Whisk until you get a creamy consistency. When this is obtained add the chestnut cream and the drop of rum (optional) and whisk again.The cream should be smooth and creamy. Then add the broken candied chestnuts and mix. Beat the egg whites with a pinch of salt. Gently and gradually add them to the chestnut cream.
Arrange the mousse obtained in verrines and place in the fridge for at least 3 hours.
You can decorate these mousses with bitter cocoa, candied chestnuts or small meringues for example…
Serve chilled and enjoy!