01 -
Melt the dark chocolate in a heatproof bowl set over simmering water until smooth.
02 -
Stir in the room temperature butter into the melted chocolate until the mixture is glossy and combined.
03 -
In a separate bowl, whisk the egg yolks together with granulated sugar until pale and fluffy.
04 -
Gradually fold the melted chocolate mixture into the egg yolk mixture until fully integrated.
05 -
Using a clean bowl, whisk the egg whites vigorously until stiff peaks form.
06 -
Gently fold the whipped egg whites into the chocolate mixture until just combined to maintain aeration.
07 -
Transfer the mixture into a lined springform pan, then refrigerate for at least 4 hours or overnight to set.
08 -
Carefully remove the set mousse from the pan, slice, and serve chilled.