375g unsalted butter, chopped
500g dark chocolate, roughly chopped
6 eggs, plus 6 extra yolks
310g caster sugar
250g cherries, pitted, halved
125g mixed fresh or frozen berries
Icing sugar, to dust
Preheat the oven to 160°C. Grease and line a 26m spring-form pan. Place butter and chocolate in a large heatproof bowl set over a saucepan of simmering water and stir for 4-5 minutes until melted and combined. Cool slightly.
Place eggs, egg yolks and 200g sugar in an electric mixer and beat on medium speed for 10 minutes or until doubled in volume. Fold one-third of the egg mixture into the chocolate mixture to loosen, then fold in the rest. Spoon batter into the prepared pan and bake for 35-40 minutes until cooked but the center still has a slight wobble. Cool completely in pan before removing.
Meanwhile, combine the remaining 1/2 cup (110g) sugar with 1/4 cup (60ml) water in a small saucepan over medium heat and simmer for 3 minutes until reduced and syrupy. Place fruit in a bowl, pour over the sugar syrup, then cool.
Dust chocolate cake with icing sugar and serve with cooled cherry sauce.