The Le Concorde cake layers crisp chocolate meringue with rich, creamy chocolate mousse creating a feast of contrasting textures. Created in 1969 by the celebrated French pastry chef Gaston Lenotre, it is debatable why the cake took the name it did. Some say that Monsieur Lenotre developed the cake and dubbed it Le Concorde because the namesake plane had taken its maiden flight that same year. Others claim the cake was created as an homage to one of Paris’s most majestic squares, Place de La Concorde, a place renowned for it’s importance in French history. In any case, the cake is so grand and impressive that it deserves a name as fitting!
For the meringue
1 ½ cup powdered sugar
4 ½ tablespoons Dutch-processed cocoa powder
6 large egg whites, at room temperature
3/4 cup granulated sugar
1 teaspoon vanilla extract
½ teaspoon salt
For the mousse
12 ounces bittersweet chocolate, finely chopped
12 ounces unsalted butter, at room temperature
9 large egg whites, at room temperature
1 1/2 tablespoon granulated sugar
5 large egg yolks, at room temperature, lightly beaten with a fork
1 teaspoon vanilla extract
½ teaspoon salt
Position the racks to divide the oven into thirds and preheat the oven to 250"F. Line two large baking sheets with parchment paper. Draw two 8 circles on one piece of parchment and another 8 inch circle on the other piece of parchment paper. Turn the parchment paper over and ensure you can see the outline. Fit a large pastry bag with a plain ½ inch tip.
Sift the powdered sugar and cocoa powder together and set aside. Using a standup mixer, whisk the egg whites on high speed until they turn opaque and form soft peaks, about three minutes. Still whisking on high, gradually add the granulated sugar and continue to beat until the whites are glossy and hold firm peaks, about five more minutes. Add the vanilla and salt. With a large rubber spatula, gently fold in the powdered sugar and cocoa mixture. Your meringue will lose a bit of volume but that is perfectly normal.
Fill your pastry bag and begin piping the batter at the center of one of the traced circles. Work your way in a spiral to the edge of the circle. The batter should be piped evenly, forming a disk about 1/3 inch thick. Refill your pastry bag as necessary and repeat the process with the remaining two circles. After the three disks have been piped, pipe as many long strips of meringue as you can on the baking sheet with the single disk.
Place the baking sheets in the oven. Bake the disks for 1.5 hours, rotating the pans front to back and top to bottom twice during the baking period. The meringues should be firm but not dark. Turn off the oven and leave the meringues to dry inside the oven (with the door closed) for at least two hours or overnight. Run a thin metal spatula under the disks and strips to loosen them from the parchment paper.
Melt the chocolate in a double boiler. Then allow it to cool until it feels warm to the touch. Using a mixer fitted with the whisk attachment, beat the butter until it is very smooth. Add the cooled chocolate in three additions, beating until the mixture is well blended. Transfer the chocolate mousse into a large bowl and thoroughly wash and dry the mixer bowl and whisk.
In the clean mixer bowl, whisk the egg whites on high speed until they hold soft peaks, about three minutes. Add the sugar and continue to whisk until the whites hold firm, glossy peaks. Add the yolks, salt and vanilla extract and whisk for another 30 seconds. With a large flexible spatula, gently add the chocolate in three additions into the egg mixture.
Place a dollop of chocolate mousse in the center of a round platter and “glue” one meringue disk to the platter. Spread about one quarter of the chocolate mousse onto the disk. Place another disk over the mousse, pressing the disk lightly so that it settles evenly on the mousse. Once again, spread another quarter of the mousse onto the disk. Place the remaining disk on top and coat the top and sides of the cake with the remaining mousse and place the cake into the refrigerator for about 20 minutes to set.
In the meantime, using a serrated knife, cut the meringue strips into pieces about ½ inch long. Remove the cake from the refrigerator and press the meringue pieces into the sides of the cake. You can serve the cake now but the meringue will be softer if you refrigerate the cake for at least one day.
Make it ahead: The meringue disks and rods can be made up to 1 week ahead and kept in an airtight box at room temperature, but the mousse needs to be used as soon as it's made. Once the cake is assembled, it can be kept covered in the refrigerator for up to 3 days. It also freezes quite nicely. When you are ready to serve, simply defrost in the refrigerator.