Tronchetto di Natale, Yule Log, Buche de Noel are just a few of the names for this famous traditional Christmas cake roll filled with jam and chocolate.
Separate the egg whites and yolks into 2 separate bowl. Beat the egg whites until stiff peaks.
Beat the yolks with the lemon zest and half the sugar until light and foamy.
Add the remaining sugar and fold in gently the whipped egg whites. Add the sifted flour a little bit at a time folding it in gently.
Spread the batter on a lined baking sheet into a rectangle about ⅓ inch thick (1 cm).
Bake in the preheated oven for 8-10 minutes (it should be light golden but not turning brown, otherwise it won't be soft). As soon as a toothpick comes out clean, it's ready to be taken out of the oven.
Lift the baking paper and transfer the cake to a clean towel. Dust the surface with 2 tablespoon of sugar, then cover it with cling wrap.
While it's still warm, start rolling it starting from one of the shorter sides. Remove the baking paper while you gently roll it.
When it's fully rolled, cover the top with cling wrap and let it cool for at least 10 minutes.
Make the chocolate ganache
Roughly chop the chocolate, then in a pot bring the cream to a simmer and turn off the heat.
Add the chocolate to the cream and let it sit, mixing once in while until the chocolate is fully melted and the ganache is shiny and smooth.
Transfer to a bowl and let it cool for about 1 hour at room temperature or 15-20 minutes in the fridge.
Assemble the yule log cake
Gently unroll the cake, then spread a thin layer of jam all over the surface.
Spread an even layer of chocolate ganache, then roll it up again without pressing too much and cover with cling wrap until you're ready to frost the cake.
Chop a piece of the rolled cake with a diagonal cut and place it on the side, to imitate a chopped branch on the log.
With a butter knife or spatula, frost the whole cake with chocolate ganache. Decorate with red currants and dusting with powder sugar.
Notes
You can prepare the cake base in advance and keep it rolled and well covered with plastic wrap. I suggest then assembling and icing the cake the same day and then storing it at room temperature until ready to serve. Just before serving, you can decorate it with red currant and powder sugar.You can store the cake for up to 5 days in the fridge, in an airtight container, or on a plate covered with foil. Bring it to room temperature before serving by taking it out of the fridge for 1-2 hours.