Melt the chocolate using a double boiler and let cool slightly for approx. 10 minutes. Add the Nefeli extra virgin olive oil and stir.
Place the egg whites in a large bowl and beat until soft peaks form and set aside.
Use another bowl to whisk the yolks, sugar and pinch of salt until pale yellow and about doubled in volume. Add the chocolate/ oil mixture and whisk until smooth.
Add a generous spoonful of the egg white mixture to the chocolate mixture. Stir until completely incorporated. Pour the chocolate mixture into the bowl of egg whites. Gently fold with a large spoon or spatula until completely combined.
Divide the mousse into 4 to 6 serving bowls and cover with plastic wrap. Chill overnight or for approx. 12-14 hours.
When the mousse is ready, add a mint leaf and serve!!!