- 300 g dark chocolate, broken into pieces, or dark chocolate drops
- 150 g butter
- 5 eggs
- 50 g caster sugar
- cocoa powder, for dusting
- 20cm (8in) diameter spring-form/loose bottomed cake tin
- Preheat the oven to 180°C (350°F/Gas 4). Line the base of the cake tin with a disc of baking parchment and grease the sides with butter.
- Place the chocolate and butter in a heatproof bowl set over a saucepan of simmering water and allow to melt, then remove from the heat and set aside.
- Place the eggs and sugar in a separate bowl and, using a hand-held electric beater or electric mixer, whisk for 7–10 minutes or until the mixture forms a light, pale mousse.
- Fold the chocolate mixture into the eggs until fully combined, then pour into the prepared tin and bake for 20–22 minutes or until the cake is almost set. Allow to cool down completely in the tin before removing, then dust with cocoa powder and cut into slices to serve.