01 - Melt the dark chocolate in a heatproof bowl over a pot of simmering water (bain-marie), stirring until smooth. Remove from heat and let cool slightly.
02 - In a clean bowl, whip the heavy cream until soft peaks form. Chill until needed.
03 - In a separate bowl, whisk the egg yolks with vanilla extract. Gradually stir in the cooled melted chocolate until fully combined.
04 - In another clean bowl, beat the egg whites with a pinch of salt until soft peaks form. Gradually add the sugar and continue beating until stiff, glossy peaks form.
05 - Gently fold the whipped cream into the chocolate mixture, then carefully fold in the beaten egg whites, one-third at a time, until fully incorporated.
06 - Spoon the mousse into serving glasses or bowls. Refrigerate for at least 2 hours, until set.
07 - In a blender or food processor, combine the raspberries, powdered sugar, and lemon juice. Purée until smooth.
08 - Strain the coulis through a fine sieve to remove seeds. Chill until ready to serve.
09 - Spoon a layer of raspberry coulis over each chocolate mousse. Garnish with fresh raspberries, chocolate shavings, and mint leaves if desired.