Add the crème fraîche and set for 5 minutes at 50° on speed 2.
Let cool then pour over the top of the cake and spread with a spatula.
Put the nutella in a piping bag, make a tiny hole at the end of the bag and draw circles.
Then, with a knife, draw lines from the center outwards.
Garnish with pieces of kinder bueno and refrigerate until ready to serve.
