Bûche de Noël is a traditional yule log cake served for Christmas in France, Belgium, Switzerland, and Canada. A thin layer of sponge cake is filled with cream and then rolled into a log. It is covered with a chocolate buttercream which is etched with a fork to resemble a bark-like texture. One end of the log is cut off and set to the side of the cake to resemble a branch. Powdered sugar is sprinkled on top to resemble snow. The cake usually is decorated with meringue stars or meringue mushrooms and candied or freeze dried berries.
Preparation time 3 hours Bake time 15 minutes Makes 12 servings
For the cake
170 grams (6 ounces or 1 cup) semisweet or bittersweet chocolate, chopped
3 tablespoons cold coffee
6 eggs, separated and at room temperature
150 grams (¾ cup) sugar
¼ teaspoon salt
For the filling
60 grams (2.1 ounces) mascarpone, at room temperature
300 milliliters (1¼ cup) cold heavy cream
⅛ teaspoon salt
30 grams (¼ cup) confectioners’ sugar, sifted
1 teaspoon vanilla
15 grams (2 tablespoons) unsweetened natural or Dutch process cocoa
45 grams (3 tablespoons) hazelnut spread like Nutella (optional)
For the bark-like covering
255 grams (1½ cups) semisweet or dark chocolate, chopped or broken into pieces
180 grams (¾ cup) heavy cream
¼ teaspoon salt
1½ teaspoons vanilla extract
60 grams (½ cup) confectioners' sugar
170 grams (1½ sticks) butter, at room temperature
Preheat the oven to 175C (350F).
Measure all the ingredients.
Line a jelly or Swiss roll pan (size: 25.4x38cm / 10x15in) with parchment, allowing for a slight overhang of paper. Butter the parchment.
To make the cake, combine the chocolate and coffee in a bowl and place over a bain-marie or a pot of simmering water until melted. Stir together until smooth and set aside to cool slightly.
In a large bowl, beat egg yolks and sugar until pale and thick, for 3–5 minutes. Stir the cooled melted chocolate into the yolk mixture until combined. Set aside.
In a separate, clean bowl, whip egg whites and salt until stiff peaks form.
Carefully fold the egg whites into the chocolate-yolk mixture using a rubber spatula. Make sure the batter is well blended but be careful not to overmix or it will deflate.
Pour the mixture into the prepared pan and even out top with a spatula or palette knife.
Bake for 15 minutes or until cake feels dry and a toothpick inserted into the center comes out clean.. Don’t over bake or the cake may crack when rolled.
** The next three steps are critical to follow so that you don't end up with cake shards as the cake layer is very delicate and prone to cracking. **
Transfer the baking pan to a cooling rack and cover the top of the cake with two layers of damp paper towels for 10 minutes. Leave the cake in the pan. The cake will deflate as it cools.
Gently remove the towels — they may have a bit of cake stuck to them (don't worry!). Sift cocoa powder (1 tablespoon) over the top of the cake. Cover the cake with a piece of new parchment paper and gently invert the pan and cake onto the parchment. Peel off the parchment paper that lined the pan and is now on the top of the cake. Sift cocoa powder (1 tablespoon) over the top of the cake, which was previously the underside. Using the new parchment paper on the bottom of the cake as an aid, roll the cake and parchment together into a "loose" log (if it is too tight, the cake may break when unrolling it later on). Roll it from the long side. Cooling it in a roll allows it to hold its shape when it’s filled and re-rolled.
Let the cake rest, seam side down, until it has cooled completely.
When the cake has cooled, prepare the filling. Combine the mascarpone, cream, confectioners’ sugar, salt, vanilla, cocoa and hazelnut spread (optional) and whip until smooth and thick.
Very carefully unroll the cake and spread the top with filling. Re-roll the cake gently (without the parchment this time!) with the filling inside and rest it, seam side down, on a serving platter or a cake cardboard.
Cover in plastic wrap and chill the cake for 1 hour to let it set.
Finally make the bark-like covering/frosting. Place the chocolate in a large heat-proof bowl. Heat the cream in a saucepan until it begins to steam. Pour the cream over the chocolate and let sit for 2 to 3 minutes. Gently stir until the chocolate is completely melted. Set aside to cool to room temperature.
Once the chocolate-cream mixture (or ganache) has cooled to room temperature, stir in the salt and vanilla and then beat the butter into the ganache slowly, adding the butter in several additions. Add the confectioners' sugar, beat until incorporated and then increase the speed and beat until fluffy (3 to 5 minutes), stopping to scrape down the sides of the bowl as needed.
Use the frosting immediately (it will stiffen quickly) by covering the log with an offset spatula. Leave the cut ends exposed. Use a fork to make textured lines resembling tree bark. Wipe the serving plate if the frosting gets all over. Depending on the thickness of your bark-like layer, you will have a lot of extra frosting.
Diagonally slice a 7½cm (3 inch) section of the log from one end. Place the angled slice log against a side of the roll, forming a branch. Fill the space between the log and branch with some of the extra frosting.
Decorate with meringue stars or meringue mushrooms, sugared or freeze dried berries and sprigs of rosemary. Dust confectioners’ sugar over the top to resemble snow.
Serve. Store leftovers in an airtight container in the refrigerator for up to 3 days. Let it come to room temperature before serving and eating again.