Preheat the oven to 160°C fan-forced and place a baking dish filled with water on the bottom shelf.

Grease a large springform tin with butter and dust with cocoa powder. Add the butter and chocolate to a large heatproof bowl and place over a saucepan of simmering water. Once starting to melt, gently stir until liquified and combined.

Take off the heat and whisk in the egg yolks until incorporated. Sift the cornflour and cocoa powder into a bowl. Add the almond meal and combine. Fold this gently into the chocolate mixture.

Whisk the egg whites to soft peaks in an electric mixer on low–medium speed. Mix the sugar and cream of tartar together in a small bowl, then add to the egg whites in four batches. Once the meringue is glossy and stiff, fold it into the chocolate mix in three stages, completely incorporating each batch before adding the next.

Place the greased tin on a baking tray and pour in the batter, filling no more than 2 cm from the top of the tin. Bake for 20–25 minutes until the edge springs back from the side of the tin and the centre is still a little wobbly – the cake should have a fudge-like texture inside.

Cool the cake to room temperature. Run a knife around the inside of the tin and remove the cooled cake. Wrap in baking paper and then plastic wrap. This is best served the next day at room temperature.

When ready to serve, preheat the barbecue on high. Sprinkle the cut side of the peaches with the sugar and char on the grill until soft with good char lines. Dust the cake with icing sugar, then serve immediately with the charred peaches and a big spoonful of double cream, if you like.