01 - Melt the dark chocolate in a heatproof bowl set over simmering water, stirring until smooth. Remove from heat and cool slightly.
02 - Whisk egg yolks with vanilla extract and half the sugar (2 tbsp) until pale and creamy.
03 - Gently fold the melted chocolate into the egg yolk mixture until thoroughly combined.
04 - Beat the egg whites with the remaining sugar (2 tbsp) until stiff peaks form.
05 - Whip the cold heavy cream until soft peaks form.
06 - Fold the whipped cream into the chocolate mixture until fully incorporated.
07 - Carefully fold the beaten egg whites into the mousse in thirds until smooth and airy.
08 - Divide the mousse evenly among six serving cups or glasses.
09 - Refrigerate for at least two hours until set.
10 - Top each mousse cup with fresh raspberries, optional chocolate shavings, and mint leaves before serving.