60g cocoa powder
30g butter, melted, plus extra for greasing
1 tsp vanilla extract
4 tbsp boiling water
6 large eggs, separated
150g caster sugar
For the filling
150g butter, softened
300g icing sugar
1 tsp peppermint essence
200g plain chocolate, 70% cocoa solids
200g milk chocolate
100g white chocolate
Step 1 – Heat the oven to 180C/fan 160C/gas 4. Grease two, 30cm x 20cm Swiss roll tins with butter. Line the base of each tin with a piece of greased greaseproof paper.
Step 2 – Sieve the cocoa powder into a small bowl, add the butter, vanilla extract and boiling water and mix together. Set aside.
Step 3 – Whisk 100g of the caster sugar and egg yolks together until light, thick and fluffy. Add the chocolate mixture and whisk until combined.
Step 4 – In a separate bowl, whisk the egg whites to stiff peaks. Add the remaining 50g of caster sugar and whisk until the sugar has dissolved.
Step 5 – Beat one third of the meringue mixture into the chocolate mixture to loosen the mix. Using a large metal spoon, fold the remaining egg whites through the mixture.
Step 6 – Divide the mixture between the two lined tins and level out. Bake for 12 – 18 minutes.
Step 7 – Remove from the oven and place on cooling racks. Cover the tins with a damp tea towel and leave to cool completely.
Step 8 – For the filling, beat the butter until soft and gradually beat in the icing sugar. Add the peppermint essence and continue beating until white, soft and fluffy.
Step 9 – Turn the cakes upside down onto 2 sheets of greaseproof paper and peel off the baking paper. Turn the cakes so that the short end is facing you. Score a line 4cm in on both short ends of both cakes. Spread the peppermint cream over the top and towards the edges.
Step 10 – Starting from the front short edge, roll up the cake, stopping in the middle. Repeat the same from the back until both rolls meet in the middle. Cut down the centre between the rolls.
Step 11 – Repeat with the remaining sponge, so you have four rolls. Trim the ends and cut each roll into three so you end up with twelve mini rolls.
Step 12 – Place the rolls, seam side down on a cooling rack and chill in the fridge for 15 minutes to firm up.
Step 13 – To finish, melt the plain and milk chocolate together in a bowl set over a pan of barely simmering water. Place the cooling rack over a baking tin (to catch the chocolate) and dip, spread or pour the chocolate over each mini roll to coat. Leave to set.
Step 14 – Melt the white chocolate in a bowl set over a pan of barely simmering water. Spoon into a small disposable piping bag and snip off the end. Pipe fine stripes across the width of the mini rolls, then leave to set.