Creating this decadent mousse is straightforward when following these steps:

1. Melt the Chocolate: Break the dark chocolate into pieces and melt it gently over a double boiler. Stir until smooth and let it cool slightly.

2. Whisk the Egg Yolks: In a large bowl, whisk the egg yolks, granulated sugar, and vanilla extract until pale and creamy.

3. Combine Mixtures: Gradually add the melted chocolate to the yolk mixture, folding gently to combine.

4. Beat the Egg Whites: In a separate clean bowl, whisk the egg whites with a pinch of salt until stiff peaks form.

5. Fold in Egg Whites: Carefully fold the whipped egg whites into the chocolate mixture in three additions. Be gentle to maintain the light and airy texture.

6. Whip the Cream: In another bowl, whip the heavy cream until it forms soft peaks.

7. Combine Cream and Chocolate: Fold the whipped cream into the chocolate mixture gently until fully incorporated.

8. Spoon into Servings: Carefully spoon the mousse into your serving glasses or bowls.

9. Chill: Cover and refrigerate for at least 2 hours, or until set.

10. Garnish and Serve: When ready to serve, garnish with chocolate shavings if desired.

These steps will guide you in creating an incredible chocolate mousse that can be enjoyed by everyone!