- 125g (4½oz) golden caster sugar, plus extra, to sprinkle
- 4 large eggs
- 40g (1½oz) plain flour, sifted
- 40g (1½oz) cocoa powder, sifted
- 1tsp vanilla extract
- chocolate curls, to decorate
- icing sugar, to dust
- for the filling
- 200ml (7fl oz) double cream
- 50ml (2fl oz) Irish cream liqueur
- for the ganache
- 300g (10oz) dark chocolate
- ½tbsp whisky
- ¼tsp vanilla extract
- 20g (¾oz) caster sugar
- you will need
- 25x30cm (10x12in) Swiss roll tin, greased and lined with baking parchment
Heat the oven to 220C, 200C fan, 425 F, gas 7. To make the cake, whisk the sugar and eggs in a large bowl until glossy and thick, around 10 minutes.
Gently fold in the flour, cocoa and vanilla – do this carefully to keep as much air in as possible. Pour into the prepared tin, spreading to each corner. Bake for 8 minutes or until springy to the touch.
Lay a large piece of greaseproof paper flat on the worktop and sprinkle lightly with caster sugar. When just cool enough to handle, turn the sponge out on to the paper. Peel off the baking parchment and roll, using the paper, from one short end to the other. Set aside, seam side down to hold the shape.
To make the filling, whip the double cream with the cream liqueur until it can just hold its shape; be careful not to over-mix.
Once the sponge has cooled, unroll and spread the cream mix all over. Roll up again and set aside.
To make the ganache, break the chocolate into pieces and set aside in a large bowl. Bring the whisky, vanilla, sugar and 125ml (4fl oz) water to the boil then pour over the chocolate and whisk well until smooth. Using a palette knife, cover the cake with the ganache, working quickly, as it sets fast. Use a fork to create a log effect. To serve, decorate with chocolate curls and a dusting of icing sugar.