For the sponge:
- 3 large eggs
- 100g caster sugar plus a little extra for sprinkling
- 75g plain flour
- 25g cocoa powder
- 15ml hot water
For the filling:
- 75g butter or margarine, softened
- 175g icing sugar
- A little milk
- Preheat oven to 220⁰C/425⁰F/Fan 200⁰C/Gas Mark 7. Line a 33.6cm x 22.5cm Swiss roll tin.
- Put the eggs and the 100g of sugar into a bowl and whisk until very light and creamy. The mixture should be stiff enough to retain the impression of the whisk for a few seconds. Sift together the flour and cocoa powder.
- Gently fold half the flour into the whisked mixture using a metal spoon.
- Fold in the remaining flour, making sure it has all been incorporated and there are no lumps. Stir in the hot water.
- Pour the mixture into the prepared tin, smoothing it over evenly and gently. Bake in the oven for 7 – 9 minutes until well risen, golden brown and spongy.
- Meanwhile, have ready a sheet of greaseproof or baking parchment and sprinkle on some caster sugar. To make the sponge pliable you can place the paper over a damp tea towel.
- Turn out the cake quickly onto the paper and trim away the edges.
- Place a second sheet of paper on top of the sponge and roll it up loosely using the sugared paper underneath as a guide. Leave to cool completely on a cooling rack, covered in the paper.
To make the filling:
- Put the butter or margarine into a bowl, sift the icing sugar and add it gradually with a little milk creaming everything together well until very smooth.
- When the sponge is completely cold gently unroll it and remove the paper. Carefully spread the sponge with the cream filling, then reroll.