Recipe: Mousse or Chocolate Cream Liège Style

Preliminary note: this recipe has a rather personal form since it was written for my children and I am too lazy to rewrite it; -)
This recipe is intended with a food processor. By hand, it's possible, but tiring, difficult.
Accompaniment (almost) essential: A speculoos.
Drink: Coffee. For me, there is only coffee that goes well with chocolate and possibly a whisky-based liqueur or liqueur with orange or mandarin flavor...And none of this contradicts an espresso...
The preparation:
Separate the egg whites from the yolks, making sure there are no particles of yolks, nor other impurities in the whites (otherwise, they will not whip into peaks).
Weigh your sugar and put it in a container.
Same with your butter cut into small pieces so it's not too hard.
Scrape your vanilla pod (if you use vanilla).
Put the whites in the food processor, equipped with the whisk, with the pinch of salt and start the food processor to whip these whites into stiff peaks.
Meanwhile, melt your chocolate cut into small pieces, either in the microwave or in a double boiler.
When your whites are whipped and are very firm, add the powdered sugar by sprinkling it slowly and letting the food processor run.
Remove your very firm whites and set aside in a bowl.
Put in the food processor bowl, without washing it, the egg yolks, the sugar, the seeds from the vanilla pod and let it run for 1 minute with the robot whisk.
While letting the food processor run, add the butter piece by piece and thus build up the cream (yolks-sugar-butter-vanilla).
From this point on, you have two solutions: the quick one or the traditional one/
The quick solution:
In the bowl, slide the egg whites in little by little until all the whites are incorporated.
The traditional solution:
Remove the cream from the