How to cook
Whip the cream with the vanilla and the essences and add the cocoa at the end, while stirring gently until everything is absorbed. Refrigerate it.
Carefully mix the cream with the egg whites and if desired, add a little more cocoa for a more intense chocolate flavor and color.
Finally, add the liquid chocolate and just lightly spread it with a spatula to make threads in the mixture or just for it to be visible, not to merge completely with the other ingredients.
Pour it into a container, that is suitable for freezing, that closes well and store it in the freezer to set and freeze.
The semifreddo does not become too hard, no matter how much time it is in the freezer - it is light and airy. But if for some reason you kept it very long and it is more frozen than it should be, you should let it defrost a bit before serving it.
Scoop from it with an ice cream scoop or a regular spoon and fill up bowls, that you can decorate to your liking.
The other option is to have frozen (but not fully) the chocolate semifreddo in a beautiful mold, covered with stretch foil, so you can easily take it out and serve it whole.