Add the butter and milk to a bowl and melt together. Sift the cake flour. Line the baking tray with baking paper. Preheat the oven to 180℃.
In a bowl, add the eggs and granulated sugar and whisk together. Halfway through whisking, mix the mixture while suspended over a pan of boiling water until it thickens enough to leave light trails.
Take off the heat and continue to whisk until the mixture forms stiff peaks. Spend the final 1 minute whisking around the edges of the batter.
Sift the powder ingredients into the mixture and fold in gently and lightly, occasionally scooping from the bottom.
Add the cocoa powder to the butter and sugar mixture from Step 1, and use a whisk to combine well.
Add 1 ladle of the egg mixture to the cocoa mixture and mix gently. Repeat this step once more before adding all of the cocoa mixture back to the egg mixture. Stir gently and remove any lumps.
If you're mixture hasn't shrunk in volume at this point, then you're doing great! Make sure to mix slowly when adding the cake flour and the cocoa mixture to the egg mixture.
Pour the batter into the baking tray. Remove any excess air pockets by lightly dropping the pan onto the work surface and then bake in a preheated oven at 180℃ for roughly 10-12 minutes.
When baked, drop the pan lightly onto the work surface once more to prevent shrinking. Wrap the sponge with Saran wrap and let it cool so that you can remove the baked surface easily.
Because you can remove the crust of the sponge nicely, we don't need to turn it over. For the filling, whip the cream, sugar and brandy together until you get stiff peaks.
Spread the cream all over the top of the sponge and add your favourite fruits. Now to roll. When rolling, push the sponge gently and roll the baking paper little by little.
Lastly, wrap the roll cake in cling film and leave to rest in the fridge for 2 hours or more to finish.
The completed roll cake.
Story Behind this Recipe
My other fluffy and moist roll cake recipe I made was rated very highly so I decided to make a chocolate version too.
When mixing in the cake flour or mixing the cocoa batter, stir gently to avoid getting rid of too many air bubbles. For Step 9, I like the crust of the sponge so I don't take it off if it won't separate easily, but if you want the roll cake to look its best, I recommend removing it.