Recipe-phile: Walk in woods inspires 'birch' log
For years I've wanted to make a "buche de noel," or French "Christmas log." It's a jelly roll cake without the jelly, both filled and frosted with chocolate buttercream. Decorated with squiggly lines for bark and cocoa-dusted meringue mushrooms, the finished cake should look like an oak log.
But a mid-December woods walk, partly a scouting trip for oak logs I could use for visual inspiration, changed my focus. I kept zoning in on birch logs in various states of decline, lounging in the snow. The white-on-white palette of the snow and the birchbark was stunning - arctic and simple - so I decided to make a "birch" de noel instead of a buche de noel.
To make it more dramatic I would lengthen the cake by stacking three jelly rolls end-to-end. And to be true to local flavors I would fill it with maple buttercream and crushed walnuts, and frost it with an off-white rum buttercream. And definitely there would be lichen, fashioned out of more buttercream. I rolled a few choice pieces of lichen-studded bark from some dead logs and put them in my pocket.
Two weeks later I baked the cakes, using a simple sponge cake. For the maple filling, I started with a simple buttercream recipe and spiked it with as much maple syrup as I could stand to spare, some brown sugar instead of white and a few drops of maple flavoring.
Ends trimmed and stacked one on top of the other, the three cakes made a log about four feet long. To make it look realistic, I cut a sliver of cake from the middle and gave it a gentle curvature, then lopped off the bottom two inches of cake, uncoiled until I reached the center and stuck that piece, like a small branch, near the top. The exposed cut sides of the cake, with the blond cake and tan filling, looked enough like the real birch wood for me to leave it alone.
I covered the rest of the cake with rum buttercream and then dragged my spatula across the log to make the bark, discovering that the sloppier I did it the better it looked. I spooned a little melted chocolate into a plastic bag, snipped it carefully at the tip, and piped very thin lines across the log. Then I piped the light-green clusters of lichen.
It was getting close, but it didn't quite look real. Then I realized that birch logs aren't really pure white, so I started dusting the frosting with cocoa and powdered sugar, and that seemed to do it.
Coincidently, when cut in half the trimmed cake ends looked just like shelf mushrooms, or polypores, especially when coated in cocoa and powdered sugar, and I think their addition really made the cake.
Laid out on a simple wooden pedestal and surrounded with candles, the birch de noel looked like an anesthetized piece of the forest. It was a bit unnerving, the way nature at close range can be, but it the pure silliness of it all swept any oddness away. I thawed the bags of fresh birch sap (or "water) I had tapped in the spring and saved for just such an occasion--though I couldn't have imagined one more apt--and we drank to the purity of the brand new year, to fresh snow, to the wonders of water from trees and bark spun from butter, and to the friends with whom we share it.
Birch de Noel
To make a three-log cake, make three pans of sponge cake and double the maple buttercream recipe.
Sponge Cake Sheet
The Joy of Cooking, by Rombauer, Rombauer Becker and Becker
3/4 cup sifted cake flour
1 teaspoon baking powder
3/4 cup sugar
5 large eggs
1/4 cup milk
3 tablespoons unsalted butter
toasted walnuts, chopped (if you have leftover candied walnuts, use those)
Preheat the oven to 400 degrees. Grease a 17 ½ x 11 ½-inch rimmed baking sheet and line the bottom with wax or parchment paper.
Measure the sifted flour and then, along with the baking powder, resift into a bowl; reserve.
Combine the eggs and sugar in a large bowl and beat until light-colored, tripled in volume and the consistency of softly whipped cream (about seven minutes in a heavy-duty mixer with the whisk attachment, about 10 minutes with a hand-held mixer).
Combine the milk and butter in a saucepan and heat until melted and steaming.
In three additions, sift the flour mixture over the top of the egg mixture and fold. Add the hot milk mixture all at once and fold in until well combined. Scrape the batter into the pan and spread evenly. Bake until the top is golden brown and springs back when lightly pressed, eight to 10 minutes.
While the cake is still hot, run a knife along the edges to release it from the pan. Immediately invert the cake onto a clean, foil-lined surface and remove the pan. When the cake is cool, peel off the paper liner.
Spread the cake with 1 ½ to 2 cups of maple buttercream filling and sprinkle with chopped walnuts.
Fold the short side of the rectangle tightly over and then continue, keeping the roll tight, until you have a cylinder. Wrap in plastic and twist the ends tightly to compact the cake. (You may reserve the cakes this way in the refrigerator up to two days, or in the freezer, before frosting.)
Prepare a batch of rum buttercream and reserve at room temperature. Take out one cup of buttercream and tint it light green to match lichen; reserve.
Trim the ends from each cylinder (reserve them for the mushrooms) and stack the logs end-to-end on a very long platter (a block of clean wood works great). Smear each end with rum buttercream and press together to make a seamless log. Cut the bottom two inches from one log and unroll until you have two inches of center; attach near the top to make a short branch.
Frost the entire cake with a thin coat of buttercream, then frost again with another smoother coat. To make the bark, roll your spatula across the log, leaving the buttercream to roll up roughly in spots, like rolled-back birchbark.
Melt 2 ounces of chocolate in a double boiler over hot water, then scrape into a plastic freezer bag. When cool enough to handle, snip the very tippy-tip of the bag. Pipe vertical lines across the log at intervals.
Cut the reserved cake-ends in half. Brush generously with cocoa and a bit of powdered sugar. Attach randomly on the cake to resemble shelf mushrooms, or polypores.
Spoon the green buttercream into another freezer bag and snip the tip at an angle. Pipe ruffled clusters of buttercream to resemble lichen.
Dust the cake randomly with cocoa, dragging your pastry brush across the log. Do the same with the powdered sugar.
2 large egg whites
1/4 cup brown sugar
1/4 cup maple syrup
1 tablespoon water
pinch of cream of tartar
1/8 teaspoon salt
1 teaspoon maple extract
1 1/2 sticks (12 tablespoons) unsalted butter, softened
Have the butter and egg whites at room temperature.
Whisk together in a large stainless steel bowl (or standing-mixer bowl, if using) the egg whites, brown sugar, maple syrup, water and salt. Set the bowl over a larger pot of simmering water and heat, whisking constantly to prevent the whites from cooking, until the mixture reaches 140 degrees on an instant-read thermometer. (It will feel very hot to the touch.)
Remove the bowl and add the cream of tartar. Whip the whites until cool and tripled in volume, about 10 minutes. The meringue should hold glossy peaks. If still warm when beaten, let sit at room temperature until cooled off.
Beat the meringue, adding chunks of room-temperature butter. Continue until all of the butter is incorporated and the buttercream is smooth. Whisk in the maple extract.
Adapted from Martha Stewart Weddings
Makes 4 cups
5 egg whites, room temperature
2 tablespoons water
1 1/4 cups sugar
2 cups (4 sticks) unsalted butter, at room temperature
3 tablespoons dark rum (may substitute 2 teaspoons vanilla extract)
1/4 teaspoon coarse salt
Whisk together in a large stainless steel bowl (or standing-mixer bowl, if using) the egg whites, water, sugar and salt. Set the bowl over a larger pot of simmering water and heat, whisking constantly to prevent the whites from cooking, until the mixture reaches 140 degrees on an instant-read thermometer. (It will feel very hot to the touch.)
Remove the bowl and whip the whites until cool, tripled in volume, and forming a meringue wth stiff, glossy peaks. This will take about 10 minutes. If still warm when beaten, let sit at room temperature until cooled off.
Beat the meringue, adding chunks of room-temperature butter. Continue until all of the butter is incorporated and the buttercream is smooth. Add the rum and beat to combine.