• Cooking oil spray, for greasing
• 3 eggs, separated
• ½ cup raw caster sugar
• 1⁄3 cup plain flour
• 2 Tbsp cocoa powder
• 1 Tbsp cornflour
• Extra 1 Tbsp raw caster sugar, for dusting
• ½ cup dark cherry jam
• Icing sugar mixture, for dusting
• 150g dark chocolate melts, melted
• ¼ cup thickened cream
• 125g dark chocolate melts
• 75g unsalted butter, chopped
• ¼ cup icing sugar mixture
• 1 Tbsp cocoa
Brandy cream filling
• 2⁄3 cup thickened cream
• 1 Tbsp icing sugar mixture
• 1 Tbsp brandy
Preheat oven to 190°C. Grease a 32 x 24cm Swiss roll tin with cooking oil spray and line base and long sides with baking paper.
Put egg yolks and 2 Tbsp of the caster sugar in the bowl of an electric mixer and whisk until pale yellow and creamy. Transfer to a large bowl. Put eggwhites into clean bowl of electric mixer and whisk until stiff peaks form. Add remaining caster sugar, in 2 batches, and beat on high for 2 minutes or until mixture is glossy and very thick. Fold eggwhites into egg-yolk mixture in 3 batches.
Sieve flour, cocoa and cornflour over egg mixture and gently fold together until combined. Spoon into prepared tin and spread to cover base. Smooth surface.
Bake for 8 minutes or until firm but still springy to touch. Meanwhile, dust a large piece of baking paper with extra caster sugar. Turn out cake, crust-side down, onto prepared paper. Set aside for 2 minutes, then gently roll up cake, starting from 1 long side. Set aside to cool to room temperature.
To make chocolate bark, wash Swiss roll tin, then grease with cooking oil spray and line base and long sides with baking paper. Spoon chocolate into prepared tin and spread. Set aside for 30 minutes to set firmly. Break chocolate into small shards.
Meanwhile, to make icing, put cream, melts and butter in a small saucepan over a low heat and cook, stirring constantly, until smooth. Transfer to a large bowl and refrigerate for 15 minutes. Add icing sugar and cocoa and beat, using an electric mixer, until thick and fluffy.
To make brandy cream, put cream, sugar and brandy in the bowl of an electric mixer and beat until firm peaks form.
Gently unroll cake. Spread jam over surface. Top with brandy cream and carefully spread to coat jam. Re-roll cake and transfer to a serving platter. Spread icing over cake. Decorate with shards of chocolate bark. Dust with icing sugar to serve.