Chocolate mousse: In a double boiler, melt the chocolate with water and coffee.
Add the yolks one by one to the melted chocolate and mix energetically.
Beat the 2 egg whites until stiff peaks form, then fold them into the previous mixture with a spatula.
Divide the mixture into 4 glasses and refrigerate for at least 3 hours.

Carambar cream: Break the Carambars into pieces, then put them in a saucepan with the 35% cream.
Melt over low heat, stirring often, until the Carambars are well melted and the cream is homogeneous.
Let it cool, then divide the preparation over the chocolate mousse.

Whipped cream: Beat the 35% cream with the powdered sugar until the beater leaves marks on the whipped cream.
Divide the whipped cream into the glasses with a piping bag, then sprinkle with chocolate vermicelli.