For the white cream, pour the condensed milk, butter and chestnuts into a pan and heat over low heat, stirring. Cook for 3 minutes after boiling.
Turn off, let cool and mix in the cream. For the dark cream, mix the milk chocolate with the semi-sweet chocolate and melt in a bain-marie. Add the Nutella® and cream, stirring until homogenized.
Make a layer at the bottom of a small dish with half of this cream. Spread the white cream and cover with the rest of the dark cream. For the topping, melt the milk chocolate in a bain-marie and spread over the dark cream.
Refrigerate for 2 hours or until it dries and forms a crust. Melt the white chocolate in a bain-marie and decorate by forming diagonal lines. Serve.
