Swiss Truffle Cake

• MAKE-AHEAD

GANACHE

1. 2 cups heavy cream
2. 4 tablespoons unsalted butter
3. 4 tablespoons light corn syrup
4. 1 1/2 pounds semisweet chocolate, finely chopped

CAKE

1. 7 ounces semisweet chocolate, finely chopped
2. 1 1/2 sticks (6 ounces) unsalted butter, at room temperature
3. 3/4 cup sugar
4. 8 large eggs, separated, at room temperature
5. 7 ounces blanched or natural almonds, finely ground
6. 2/3 cup fine dry bread crumbs
7. 1 tablespoon unsweetened Dutch process cocoa powder

1. In a medium saucepan, bring the cream, butter and corn syrup to a boil over moderate heat. Remove from the heat, add the chocolate, stir once and let stand for 5 minutes. Whisk until smooth and strain into a bowl. Refrigerate until thickened, about 2 hours.
2. Preheat the oven to 350° and position a rack in the middle. Butter a 10 1/2 -by-15 1/2 -inch jelly-roll pan and line the bottom with parchment paper. Butter the paper. In a small bowl set over a saucepan of hot but not simmering water, melt the chocolate, stirring occasionally. Let cool.
3. In a large bowl, using an electric mixer, cream the butter with half of the sugar. Beat in the chocolate then beat in the egg yolks 1 at a time. Combine the almonds and bread crumbs and stir them into the batter.
4. In another large bowl, whip the egg whites until they hold very soft peaks. Gradually beat in the remaining sugar until the whites hold firm peaks. Stir one-quarter of the whites into the batter, then fold in the remaining whites with a rubber spatula.
5. Spread the batter evenly in the prepared pan. Bake for 20 minutes, or until the cake is firm and no longer sticky when touched lightly in the center.
6. Let the cake cool in the pan for 2 minutes, then loosen the sides with the tip of a knife. Invert the cake onto a rack and peel off the paper. Cover the cake with another rack and turn it right side up. Let cool to room temperature.
7. To assemble the 2 cakes, halve the layer crosswise. Cut each half crosswise into thirds, each about 31/2 by 7 3/4 inches. Cut 2 pieces of stiff cardboard about 1/4 inch larger than the layers. Place 1 cake rectangle on each cardboard.
8. Gently whisk the ganache to a spreading consistency. Using a long metal spatula, spread each of the 2 rectangles of cake with about 3 tablespoons of ganache. Cover with 2 more layers of cake and ganache. Generously frost the sides of the 2 cakes with ganache.
9. To finish, spoon the remaining ganache into a pastry bag fitted with a 1/2 -inch plain tip and pipe thick diagonal strips on top of the cakes . Refrigerate the cakes to set, about 2 hours. Just before serving, dust the tops of the cakes with cocoa powder.