First, cut off a few crumbly strips of chocolate with a sharp knife and set them aside for decoration.
Then melt the rest of the chocolate together with the soy milk in a water bath. The chocolate mass is supposed to cool down while the egg whites are being made.
Put the aquafaba together with the lemon juice and the sugar in a mixing bowl and beat it with a hand mixer until stiff. That can take 10 minutes. It is important that the bowl and stir bars are absolutely clean (especially free of grease). The lemon juice ensures that the aquafaba sets a little faster and is more dimensionally stable.
Now the chocolate mass should only be lukewarm at most. This is important so that the egg white does not liquefy again in the next step. Gradually add the chocolate mixture to the egg whites and carefully fold it in. Don't stir too long!
Now you fill the finished chocolate mousse into the containers in which you want to serve it later, and sprinkle the chocolate set aside over it. Then put the chocolate mousse in the cold for a few hours.