Melt chocolate: In a heatproof bowl, melt white chocolate over a pot of simmering water (double boiler) or in short bursts in the microwave. Let it cool slightly.
Whip cream: Whip ¾ cup of the heavy cream to soft peaks. Set aside.
Beat egg yolks: In a small bowl, whisk egg yolks with vanilla. Gradually fold into melted chocolate until smooth.
Beat egg whites: In a clean bowl, beat egg whites with sugar and a pinch of salt until stiff peaks form.
Combine: Gently fold whipped cream into the chocolate mixture. Then fold in the egg whites carefully to keep mousse airy.
Chill: Spoon into serving glasses or bowls and refrigerate for at least 2–3 hours until set.
Serve: Top with shaved white chocolate, berries, or a drizzle of raspberry sauce if desired.