In a small saucepan, heat 1/2 cup of the heavy cream until it just begins to bubble around the edges.

Remove the saucepan from heat and add the chopped chocolate. Stir until the chocolate is melted and the mixture is smooth. Set aside to cool for 10 minutes.

In a medium mixing bowl, beat the remaining 1/2 cup of heavy cream until soft peaks form. Add the sugar and vanilla extract and continue beating until stiff peaks form.

In another medium mixing bowl, beat the egg whites and salt until stiff peaks form.

Fold the cooled chocolate mixture into the whipped cream, then fold in the beaten egg whites, taking care not to overmix.

Spoon the mousse into serving glasses or bowls and refrigerate for at least 2 hours, until set.

Serve chilled and enjoy!