Preheat oven to 350°F (175°C) and grease a round cake pan.

Melt dark chocolate in a heatproof bowl over simmering water or in the microwave. Let cool slightly.

Whip heavy cream until soft peaks form; set aside.

In another bowl, beat eggs and sugar until creamy. Fold in melted chocolate, then gently fold in whipped cream until combined.

Pour half of the mousse into the prepared pan, layer with half the raspberries, and add remaining mousse on top.

Refrigerate for at least 4 hours or overnight before serving.