The filling of this simple-to-make Swiss roll is subtly laced with Irish cream liqueur to add to the festive spirit. Piped chocolate icing forms the bark – an easy way to turn the roll into a log in an instant. Take care not to knock out the air from your sponge mixture as you fold in the flour – once the sponge is baked, the tiny pockets of air keep the sponge pliable enough to roll without cracking, while retaining a light and fluffy texture.
Heat the oven to 190°C/170°C fan/375°F/Gas 5.
Make the sponge. Crack the eggs into the bowl of a stand mixer fitted with the whisk. Add the sugar, then whisk the mixture on high speed for 2–3 minutes, until it is pale in colour, thick, and leaves a ribbon trail when you lift the whisk. Sift in the flour, cocoa powder and salt and, using a large metal spoon, fold everything together, until all the cocoa and flour are incorporated into the egg mixture and no streaks remain. (Be careful not to beat any of the air out of the mixture.)
Pour the mixture into the lined Swiss roll tin and spread it out into the corners in an even layer. Bake on the middle of the oven for 10–12 minutes, until the sponge is well risen and firm to the touch and the sides are shrinking away from the edge of the tin.
Place a piece of baking paper larger than the Swiss roll tin on the work surface. Dust it generously with cocoa powder, then carefully invert the sponge onto the paper and remove the lining paper.
Using a sharp knife, score a line 2cm in along one of the short edges (take care not to cut all the way through the sponge). Starting with this edge, tightly roll up the sponge using the paper to help you and with the paper inside. Then, transfer the roll to a wire rack and leave it to cool completely.
While the sponge is cooling, make the icing. Melt the chocolate in a heatproof bowl set over a pan of gently simmering water. Stir until smooth, then remove from the heat and leave to cool.
Place the butter, icing sugar and cocoa powder in the bowl of a stand mixer fitted with the beater attachment. Mix on low speed for 1 minute, until the icing sugar and cocoa powder are incorporated into the butter, then increase the speed to medium and mix until the icing is light, soft and smooth. Add the cooled, melted chocolate and mix on low speed until incorporated. Spoon the mixture into the large piping bag fitted with the large open star nozzle and set aside until needed.
Make the filling. Pour the cream and Irish cream liqueur into the bowl of a stand mixer fitted with the whisk. Whisk on medium speed until firm peaks form.
Unroll the cooled Swiss roll sponge and remove the paper. Spread the whipped cream on top in an even layer, all the way to the edges, and then re-roll the sponge tightly with the cream inside. Carefully transfer the filled roll to a serving plate.
Pipe long, thick lines of chocolate icing along the length of the Swiss roll, covering the top and sides of the sponge completely so that the icing looks like the bark of a tree. Trim each end of the sponge to reveal the neat swirl of cream filling inside the log.
To decorate, dust the work surface with cornflour and, using a rolling pin, roll out each piece of fondant until it is 3mm thick. Using the stocking-shaped cutter, cut out 6 white Christmas stockings, and 1 red, 1 orange, 1 yellow, 1 green, 1 blue and 1 purple stocking. Keep the trimmings of the green and red fondant (you can discard the rest).
Using the small craft knife, cut the tops (cuffs) off the white stockings. Using the paintbrush, brush the tops of the coloured stockings with a little water and stick the white cuffs on top to resemble the ‘fluffy’ cuff of each Christmas stocking.
Cut a little piece of the heel and a little piece of the toe off each white stocking and stick these to the heel and toe of each of the coloured stockings. Discard the rest of the white fondant.
Using the small holly-leaf cutter, cut out 6 holly leaves from the remaining green fondant (re-roll it if necessary) and, using your fingertips, roll 6 small balls using some of the remaining red fondant to form tiny holly berries.
To assemble the decoration, position the strawberry lace at the top of one long side of the log, in a wavy line, like a piece of string. Arrange the fondant stockings along it (red, orange, yellow, green, blue, purple), to give the impression they are hanging off the lace. Trim the ends of the lace, then arrange 3 holly leaves and 3 holly berries at each end. Dust the log with icing sugar, like newly fallen snow, to finish.