200g good-quality dark chocolate, chopped
5 eggs, separated
110g (1/2 cup) caster sugar
2 x 120g punnets raspberries
250ml (1 cup) thickened cream
1 tablespoon cocoa powder, to dust
1. Preheat oven to 180Â°C (conventional). Grease a 23cm x 33cm shallow baking tray. Line the base and sides with one piece of non-stick baking paper – cut corners to fit and let ends overhang.
2. Place the chocolate and 60ml (1/4 cup) water in a heatproof bowl over a saucepan of simmering water. Stir until the chocolate melts. Remove from the pan and set aside to cool slightly.
3. Use electric beaters to whisk the egg yolks and sugar until thick and pale, and a ribbon trail forms when the beaters are lifted. Fold in the chocolate mixture.
4. Use clean electric beaters to whisk the eggwhites in a clean, dry bowl until soft peaks form. Fold half the eggwhites into the chocolate mixture. Fold in the remaining eggwhites until just combined. Pour into prepared tin and smooth the surface. Bake in preheated oven for 20 minutes or until a skewer inserted into the centre of cake comes out clean. Remove from oven and cover immediately with non-stick baking paper, then a damp tea towel. Set aside for 30 minutes.
5. Roughly mash half the raspberries. Use clean electric beaters to whisk the cream until firm peaks form. Gently swirl the mashed raspberries through the cream.
6. Tear off a piece of non-stick baking paper larger than the cake and dust with cocoa. Remove the tea towel and paper from the top of the cake and turn it onto the cocoa-dusted paper. Remove the paper from the base of the cake.
7. Spread with raspberry cream and sprinkle with the whole raspberries. Starting at a short end, roll up firmly, using the paper as a guide. Wrap the paper firmly around the roll to hold it and place, seam-side down, on a tray. Place in the fridge for at least 2 hours before serving.