Making chocolate mousse is easier than you might think. Follow these step-by-step instructions to achieve that perfect airy and creamy texture.

1. Prepare the Chocolate:
   • Break the dark chocolate into small pieces and place them in a heatproof bowl.
   • Melt the chocolate using a double boiler or microwave, stirring occasionally until smooth. Set aside to cool slightly.
2. Whip the Egg Whites:
   • In a clean, dry bowl, beat the egg whites with a pinch of salt until soft peaks form.
   • Gradually add half of the sugar and continue beating until stiff, glossy peaks form. Set aside.
3. Prepare the Egg Yolks:
   • In a separate bowl, beat the egg yolks with the remaining sugar and vanilla extract until pale and thick.
4. Combine the Chocolate and Egg Yolks:
   • Gently fold the melted chocolate into the egg yolk mixture until well combined.
5. Incorporate the Egg Whites:
   • Carefully fold the whipped egg whites into the chocolate mixture, in three batches, ensuring not to deflate the mixture.
6. Whip the Cream:
   • In a chilled bowl, whip the heavy cream until soft peaks form.
7. Combine All Components:
   • Gently fold the whipped cream into the chocolate and egg mixture until no streaks remain.
8. Chill the Mousse:
   • Divide the mousse into individual serving dishes or one large dish.
   • Cover with plastic wrap and refrigerate for at least 4 hours or overnight for best results.