Place chocolate and butter in a heatproof bowl. Place a bowl over a pot of simmering water, then slowly melt 200g good-quality dark chocolate and 200g butter together. Stir occasionally to ensure everything is melted. Remove the bowl from the heat and leave to cool for about 10 mins.

In a large bowl, use an electric whisk to whisk 4 eggs, 4 egg yolks, and caster sugar together until pale and thick. Add the chocolate mixture and whisk to combine. Fold through the flour and cocoa powder with a spatula.

Remove the inner pan and lightly spray with cooking spray. Return to the rice cooker and pour in the cake batter.

Select the 'Cake/Bread' setting and dial in 50 minutes.

When the cake is ready, remove the inner pan from the rice cooker. Place a plate over the top of the inner pan and flip the cake out. Place a serving plate on top of the cake and flip again.

To serve, dust with icing sugar, and serve with fresh raspberries and cream or ice-cream if using. Serve immediately.