1. Preheat the oven to 180 ° C. Butter and line a 20-22 cm round cake mold with baking paper.
2. Place the chocolate, butter and a pinch of salt in a heatproof bowl over a pot of simmering water, making sure the base of the bowl does not touch the water. Stir until melted and well mixed, then remove from heat and let stand until completely cooled.
3. Place the egg yolks and sugar in a large bowl and whisk until thick and pale. Beat egg whites in a separate bowl with a pinch of salt until stiff peaks form. Add the cooled chocolate mixture to the egg yolk mixture and stir to combine well. Sift the flour over the chocolate mixture and stir until just combined. Add a third of the beaten egg whites and stir into the mixture until well combined. Add the remaining beaten egg whites and fold in very gently so as not to expel all the air. Pour mixture into prepared pan and bake for 30 minutes or until just firm. Take out of the oven and let cool in the mold. Once cooled, it will sink slightly.
4. To serve, garnish the cake with fresh berries and sprinkle with icing sugar.
Silvia Colloca shares her Italian family secrets in the brand new second season of Cook like an Italian.