Cocoa Swiss Roll Sponge
- Pre-heat the oven.
- Rub some butter around the inside of a 23 x 33cm/9 x 13” baking tray or insert a baking liner.
- Put the cocoa and water into a bowl, mix into a smooth paste and set aside.
- Break the eggs into a large bowl and whisk using electric beaters.
- Add the caster sugar and whisk for a minute.
- Sieve the flour into the bowl and whisk lightly.
- Add the prepared cocoa mixture and whisk again.
- Tip the mixture into the prepared tray and spread it out to the edges.
- Bake for 13-15 minutes.
- Leave the cake in the tray for 2-3 minutes then carefully tip it out onto a clean tea towel.
- Using the tea towel to support the sponge, gently roll it up from the short end and leave to cool.
Vanilla Buttercream Filling and Topping
- Sieve the icing sugar into a mixing bowl, add the softened butter and vanilla extract.
- Beat together until smooth.
- Gently unroll the cold sponge, spread the buttercream evenly over the inside, then roll the sponge up quite tightly from the short end, making sure the filling stays inside. You can use the tea towel to help with this.
- Dust the top with icing sugar before serving.
23 x 33cm/9 x 13” baking tray, electric beaters, clean tea towel and 3 x mixing bowls
200°C, Fan 180°C, 400°F, Gas 6