Fran’s Blanc et Noir Cake

With sharp corners and graphic design, this layer cake is an elegant showstopper. For such a sophisticated-looking cake, the Blanc et Noir is surprisingly user friendly. It freezes well, cuts easily into thin, clean slices, and is a melt-in-your-mouth delight. Each bite is like biting into a perfect baked truffle.
Even those who don’t normally like white chocolate love the white chocolate ganache between its layers. It’s much lighter than a buttercream and the taste is all chocolate, rather than the cloying sugary sensation you often get with fillings. It’s worth shopping for a good quality white chocolate (we’re of course partial to our White Chocolate Baking Bar). It makes all the difference.

Serves 12 to 16

Ingredients

White-Chocolate Ganache Filling

½ cup heavy cream
8 ounces white chocolate, finely chopped

Noir Cake Layers

8 ounces semisweet chocolate, finely chopped
1 stick (8 tablespoons) unsalted butter, room temperature
5 large eggs, separated
½ cup plus 1 tablespoon sugar
1 recipe Dark-Chocolate Ganache Glaze

White Chocolate for Writing

2 ounces white chocolate, roughly chopped
2 teaspoons vegetable oil

Directions

To Make the Filling

In a saucepan, heat the cream over medium-high heat just until it begins to boil. Remove from the heat and add the white chocolate, stirring until the chocolate is smooth and melted. Pour into a small bowl and cover with plastic wrap touching the surface to prevent a skin from forming. Let the ganache set up at least 12 hours or overnight at room temperature.

To Make the Cake

Position a rack in the middle of the oven and preheat the oven to 300°F.
Lightly butter a 9-by-13-inch or quarter-sheet pan and line with parchment paper. Then lightly butter the parchment paper.
In a double boiler melt the chocolate over low heat. Remove the boiler top when the chocolate is nearly melted and continue stirring until completely smooth. Add the softened butter in 3 parts, stirring until no visible traces of butter remain. (If the butter begins to melt and separate, stop and allow the chocolate more time to cool.) The finished mixture should be glossy and smooth. Set aside to cool until the mixture is the consistency of softened butter. Briefly return to the double boiler if it begins to thicken too much. In a mixer fitted with a whisk attachment, whip the eggs yolks with half the sugar at medium-high speed, increasing to high speed until pale yellow and tripled in volume, about 5 to 6 minutes.
Remove the bowl from the mixer. With a rubber spatula fold in the melted chocolate mixture. The mixture should be smooth and glossy.
Clean the whisk and in another clean bowl begin whipping the egg whites on medium-high speed, increasing the speed and allowing them to become quite frothy. Slowly add the remaining sugar and continue whipping until the peaks are still and creamy.
Lighten the chocolate mixture by quickly folding in a quarter of the whites until smooth and no traces of white remain. Then gently fold in the remaining whites in 3 parts, trying not to overmix and lose the volume. Evenly spread the batter into the prepared pan. The pan will be two-thirds full.
Bake for 20 to 25 minutes. The cake will rise above the edges of the pan, and a light crust will form on top. A cake tester inserted in the center will have a few moist crumbs.
Let the cake cool in the pan at room temperature for 10 minutes. Then chill until thoroughly cold, 4 hours or overnight. Wrap tightly in plastic wrap if chilling for longer than 4 hours. (The layer can be wrapped in plastic once cooled and placed in freezer up to a week prior to assembly.)

To Assemble the Cake

Have ready the White-Chocolate Ganache Filling.
To remove the well-chilled cake from the pan, run a thin-bladed knife around the edges. Place the bottom of a baking sheet over the cake and invert. Remove the parchment paper.
Place the filling in a mixing bowl. It should be the consistency of softened butter. (If not thick enough, stir and let sit longer to thicken.) With a whisk attachment or using a hand mixer, mix on high speed until the ganache is lighter in color and texture and soft peaks form, 2 to 4 minutes. Stop several times and scrape down the side of the bowl.
Using a ruler and the tip of a paring knife, mark the cake in thirds across its width. Cut the cake with a serrated blade into 3 approximately 4-inch-wide sections.
Place one chilled layer of the cake on the serving plate or on a 4-by-8-inch cardboard cake board. With a metal spatula, spread half of the white ganache filling on the layer. Top with the second chilled cake layer and spread with the remaining filling. Top with the last child cake layer.
Using a thin-bladed knife, trim the sides of the cake. Let set in the refrigerator at least 1 hour.

To Finish the Cake

Make the Dark-Chocolate Ganache Glaze.
Pour about ¼ cup of the glaze into a small bowl and place in the refrigerator to chill for approximately 25 minutes. Set aside the remaining ganache to cool about 30 minutes, gently stirring occasionally until it thickens and ribbons off the end of the spatula, 80-85°F.
Meanwhile make White Chocolate for Writing

To Make Writing Chocolate

In a small bowl over simmering water, melt the chocolate. Remove from the heat, add the vegetable oil, and stir with a spatula until smooth. Set aside.
With an offset spatula, thinly coat the top and sides of the finished cake with the ¼ cup chilled ganache glaze. Transfer to a cooling or pouring rack positioned over a rimmed baking sheet.
Slowly and evenly pour the rest of the glaze around the sides of the cake, being careful to cover all the corners. Then pour the remaining glaze down the center using a metal spatula to spread the glaze evenly over the top, letting the excel run down the sides. Before glaze sets, decorate.
Pour the writing chocolate into a small parchment paper cone. Pipe 3 thin white parallel lines, ¼ inch apart, lengthwise, down the center of the cake over the soft glaze. Working quickly, with a toothpick draw small figure eights crosswise through the ganache and white stripes all along the cake’s length.
Chill for 1 to 2 hours to set. Remove half an hour before serving. Can be stored in the refrigerator for up to 3 days.