Transfer the chopped chocolate to a glass bowl. Place it over a pan of gently boiling water and melt the chocolate au bain marie.
Stir in the olive oil as soon as the chocolate has melted entirely.
Add the whipped cream to the melted chocolate and olive oil mixture and stir gently for 1 minute. Don’t overbeat the cream. The air bubbles inside make sure the chocolate mousse stays light and fluffy.
Let the chocolate mousse set for at least 3 hours at room temperature, don't put it in the fridge.
Then scoop the mousse into glasses. Garnish with a little sprinkle of salt right before serving.