A chocolate roulade is traditional at Christmas and this one is even more heavenly with a mascarpone filling. While the recipe looks long, it isn’t actually that difficult to make.
Knob of butter, melted, for greasing
6 eggs, separated
150g (5 1/2 oz) caster sugar
1 tsp vanilla extract
55g (2oz) cocoa powder
Icing sugar, for dusting
150g (5 1/2 oz) mascarpone
50ml (2 fl oz) cream
2 tbsp icing sugar
1/2 tsp vanilla extract
55g (2oz) milk chocolate, chopped
55g (2oz) dark chocolate, chopped
170g (6oz) butter, softened
150g (5 1/2oz) icing sugar
Icing sugar or white chocolate shavings, for decoration
1. Preheat the oven to 180c/350f/gas 4/fan 160. Line a swiss roll tin with baking parchment, with approx 5cm (2 in) coming up over the edges of the tin. Fit the parchment into the corners of the tin, making diagonal cuts inwards from each corner to help the paper to fit snugly into the tin. It is also helpful to staple or paper clip the corner edges of the baking parchment together. Brush the bottom of the baking parchment with melted butter.
2. Put the egg whites in a clean bowl with a large pinch of salt and whisk the egg whites to soft peaks then set aside. Put the yolks, sugar and vanilla in a large bowl and beat until pale, trebled in volume and mousse-like. Sift over the cocoa powder and add a large spoonful of the egg whites and fold in. Old in the remaining egg whites and pour the batter into the prepared tin. Spread the batter out in an even layer then lightly tap the tin on a work surface a couple of times.
3. Bake the cake for 20-22 minutes, until risen and firm to the touch. While the cake is baking lay a clean tea towel out on a flat surface and dust generously with icing sugar. When the cake has baked, remove from the oven and allow to cool for 5 minutes then turn the cake out onto the tea towel and slowly and carefully peel off the baking parchment. Take one of the long edges of the tea towel and fold it over the long edge of the cake then roll the cake up from the long edge in the tea towel and leave to cool completely.
4. To make the filing, put the mascarpone in a bowl and beat briefly to soften. Add the remaining ingredients and beat for 1-2 minutes until thick. To make the icing, put the chocolates in a bowl sitting over, not in, a pan of warm water. Melt the chocolate, stirring occasionally, then remove from the pan and leave to cool slightly. Beat the butter until pale then beat in the melted chocolate followed by the icing sugar. If the icing is very soft then refrigerate for 10-15 minutes.
5. Unroll the cooled cake completely and spread the filling over the surface, leaving a 1/2 cm border on each short side. Roll the cake up again tightly from the long edge (without the tea towel). Don’t worry if the cake cracks a bit as it will be iced. Transfer the cake to a serving plate. For a traditional presentation you can cut a 10cm piece from one end of the cake and sit it on the side of the remaining cake, like a branch on a log. However you can also leave it as one long swiss roll, if you prefer.
6. Spread the cake generously with the icing and use a fork to make lines like bark on the log and rings on each end. For a neater presentation, tuck a piece of baking parchment down each side of the log and pull it away after icing. Refrigerate for around 1 hour to allow the icing to set. Decorate the cake with a dusting of icing sugar or shaved white chocolate “snow” (see the snowball recipe for instructions on how to make chocolate shavings).
Party planning – the log can be made a day in advance and kept in the refrigerator. Remove from the refrigerator around 30 minutes before serving. Leftovers will keep for 2 days in the refrigerator and individual slices can be frozen for up to 1 month, wrapped in foil. Defrost overnight in the refrigerator.
Preparation 45 minutes
Cooking 22 minutes
Makes 12 portions