We have been having buche de noel as our Christmas dessert since I was a wee thing, originally having picked up the habit during our brief sojourn in Montreal before we moved on to California. Although there are a lot of versions of buche de noel kicking around, ours has been the exact same nearly all my life: chocolate genoise rolled around lightly sweetened whipped cream, covered in a cocoa frosting raked with a fork to simulate bark.
It’s delightful, it’s tradition, the leftovers make an amazing Boxing Day breakfast, and for most of my life, I never even considered messing with it. Last year, though, I was feeling a little sacrilegious, and decided to see what a Black Forest variation would be like. I added a jar of sour cherries to the filling, and I brushed the cake with a syrup made from the cherries’ liquid fortified with sour cherry jam and kirsch. I loved the results, so this year I went even further over the top, finally getting around to making the meringue mushrooms that normally decorate the cake, but which we’d never bothered with.
This cake is, I freely admit, a pretty massive production, which is why it’s a holiday activity. It involves at least a full day of work, and more likely two: the meringues the day before and the cake the day of serving. I know you’re not going to do this more than once a year, and you probably won’t do it at all, but if you do, believe me when I say it’s worth it. It’s fantastically delicious, and there’s nothing like the gloat factor from pulling off something that looks this impressive.
If you do decide to make this Yule log over one of the remaining ten days of Christmas, one note about the meringues: they’re a mashup of a Jacques Torres and an Alice Medrich version, which is why that part of the recipe below is by weight in grams instead of volume. I may revise this post later to give measurements instead, but as long as you have a kitchen scale, the current version should work well for you. You can also scale the meringues down more easily with weights in grams, which you may want to do since you don’t really need anywhere near that many. I only made that big a batch because I had 5 whites left over from a batch of hollandaise, and I plan to take the many leftover mushrooms to work on January 2nd as a lighter offering for those coworkers who will insist on making New Year’s resolutions (bah, humbug!).
Black Forest Buche de Noel
(Meringue mushrooms adapted from Jacques Torres, Dessert Circus at Home, 1999 and Alice Medrich, Chewy Gooey Crispy Crunchy, 2010)
Serves, at a minimum, 12 drummers drumming
For the meringue mushrooms
5 large egg whites, at room temperature
168 grams granulated sugar
168 grams sifted confectioner’s sugar
Cocoa powder for dusting
115 grams good-quality dark chocolate, finely chopped
For the cake
The cherry syrup
1 24-ounce jar Morello or other sour cherries in light syrup
¼ cup sour cherry jam
1-2 stiff shots of kirsch, to taste
The chocolate genoise
5 large eggs, separated and at room temperature
2/3 cup granulated sugar
3 tablespoons unsweetened natural cocoa
2 tablespoons unbleached all-purpose flour
1 cup heavy cream for whipping
1 tablespoon powdered sugar
1 teaspoon vanilla extract
1½ cups confectioner’s sugar
6 tablespoons unsweetened natural cocoa
Pinch of salt
3-4 tablespoons milk
1 teaspoons vanilla extract
3 tablespoons unsalted butter, softened
1. Make the meringue mushrooms
Preheat the oven to 250F and line 4 baking sheets with parchment. Beat the 5 egg whites at medium speed in a standing mixer fitted with the whisk attachment until foamy, then start adding in the granulated sugar a tablespoon at a time. Increase the speed to medium high and beat until stiff and glossy peaks form, about 5 minutes. Lower the speed to low and whip 2 more minutes, stopping if the meringue starts to look dry. Gently fold in the confectioner’s sugar with a rubber spatula, and spoon the meringue into a pastry bag or gallon-sized zip-top bag fitted with a ½ inch round decorating tip.
To make the mushroom caps, hold the piping bag just above the surface of the paper and squeeze the bag until the meringue forms a mound the size you want. Stop piping and skim the tip along the surface before lifting to prevent a peak from forming. Repeat with more caps, set an inch apart, until you have filled two of the sheets. To make the stems, hold the bag perpendicular to the sheet and squeeze a quarter-sized amount of meringue, then pull up to create a cone. (Don’t worry if the tips bend over, since they’ll be sliced off later anyway.) Make significantly more stems than caps, since you’ll need extras as insurance against breakage, etc. Lightly dust the caps with the cocoa and blow off the excess while holding the sheet over the sink. Bake the meringues at 250 F for an hour until firm and dry, lowering to 200 if you see signs of browning. Turn off the oven and leave to cool for another hour.
When ready to assemble the mushrooms, melt the chopped chocolate in a liquid measuring cup in the microwave at low power in 30-second increments, stirring between zaps, until only a scattering of larger unmelted pieces remain. Use an immersion blender to finish the melting process and temper the chocolate, and set the measuring cup in a bowl of warm water to keep it liquid as you work.
Spread a thin layer of chocolate on the bottom of a meringue cap, carefully saw the pointy tip off a corresponding stem with a sharp knife to create a flat surface, and stick the cut end into the chocolate, setting it back upside down onto the baking sheet until the chocolate has hardened and the halves of the mushroom are firmly stuck together. Repeat with remaining meringues, and store in airtight containers until ready to serve the cake.
2. Make the cake
To make the soaking syrup for the cake, drain the cherries very well in a strainer set over a measuring cup, then set them aside for the assembly stage. In a small saucepan, combine their syrup with the cherry jam, and simmer vigorously until reduced by half. (My jar yielded about 1½ cups of syrup, which boiled down to ¾ cup). Cool briefly before adding the kirsch to taste, then leave to cool completely while preparing the cake.
Preheat the oven to 350 F. Grease a standard rimmed baking sheet, line the bottom with parchment, and lightly grease and flour the paper.
Beat the egg yolks at high speed in a standing mixer until light and fluffy. Gradually add the granulated sugar and continue beating until thick and pale and at the “ribbon” stage, in which the drips from the beaters briefly form a ribbon on the surface of the mixture. Combine the cocoa and flour, sift over the yolks, and mix in at low speed. In a clean bowl with the whisk attachment, beat the egg whites until soft but not dry peaks form. Use the whisk attachment to stir a third of the whites into the yolk mixture to lighten it, then gently fold in the remaining whites with a spatula until the batter is mostly uniform. (A few streaks of unincorporated whites is preferable to over-mixing and losing volume, but you don’t want any large lumps of egg whites floating around.)
Spread the batter evenly in the prepared sheet pan, rapping it once firmly against the counter to pop any too-large air bubbles. Bake until the cake begins to just pull away from the sides and the top springs lightly back when pressed gently with a fingertip, approximately 15 minutes. Cover the surface with another piece of parchment paper and cool completely on a wire rack.
3. Fill the cake
Sprinkle a piece of parchment paper lightly with powdered sugar and invert the cake onto the sugared paper. Gently peel off the parchment the cake was baked in, tearing it off in smaller pieces if necessary to prevent the cake ripping. Lightly brush the surface of the cake with the syrup until moist but not soaked. Beat the cream with the sugar and vanilla until stiff and spread evenly over the surface of the cake, then dot the cream with the drained cherries.
Using the parchment the cake is siting on to help you, roll the cake over the filling along the long edge, ending with the seam side down. With your knife at a diagonal, cut a piece several inches long off each end of the roll, to form the branches of the log. Carefully transfer the largest piece onto a serving platter, then set the end pieces on opposite sides of the “trunk”, cut sides facing out and staggered slightly to avoid unnatural symmetry. Cover the cake with plastic and refrigerate until it firms up, at least as long as it takes to prepare the frosting, but not more than a few hours.
4. Frost the cake
In a mixer fitted with the paddle, combine the sugar, cocoa and salt. Add the milk and vanilla and blend until smooth, then beat in the butter until a fluffy spreading consistency is reached, adding a little more milk if necessary.
Frost the cake with a gentle hand to prevent any tearing the sponge, also avoiding the cut ends so that the cream filling doesn’t streak the frosting white. Using a fork or a cake comb, run along the frosting to create a bark-like effect. Cover again with plastic and refrigerate until ready to serve.
5. Decorate and serve
Just before serving, decorate the cake and its platter with clusters of the meringue mushrooms. Have extra mushrooms on the side to add to each plate as you serve slices to your guests.
For a really helpful visual with tips on how to pipe and assemble the mushrooms, see this video featuring Alice Medrich.
You will have plenty of cherry soaking syrup left over, which is a great addition to holiday cocktails or mixed with plain soda. If you would like it to be non-alcoholic, you could leave out the kirsch, since there will be plenty of cherry flavor even without it.
Don’t be tempted to decorate the cake with the mushrooms too far ahead. They should be added just before serving so they don’t absorb too much moisture from the cake and go soggy. Any meringue mushrooms not used to decorate the cake or added to each plate when serving should be kept in airtight containers, where they will stay crisp for quite a long time.