6 large eggs, separated, at room temperature
1/4 teaspoon cream of tartar
3/4 cup granulated sugar, divided
1/3 cup Dutch-process cocoa powder, such as Droste, sifted
1 teaspoon unflavored gelatin
2 tablespoons boiling water
1 1/2 cups heavy cream
2 tablespoons confectioners’ sugar
Grated zest of 1/2 orange
1/2 teaspoon vanilla extract
1/2 cup heavy cream
6 ounces bittersweet chocolate, finely chopped
2 tablespoons light corn syrup
1 tablespoon Grand Marnier or other orange-flavored liqueur, or frozen orange juice concentrate, thawed
Sprigs of fresh juniper or pine for garnish
2 tablespoons Dutch-process cocoa powder, such as Droste for garnish
1. To make the chocolate roll, position a rack in the center of the oven and preheat to 350° F. Lightly butter a 15 1/2 X 10 1/2 X 1-inch jelly roll pan. Lightly butter the pan and line with waxed paper.
2. In a greasefree, large bowl, using a hand-held mixer at low speed, beat the egg whites until foamy. Add the cream of tartar and increase the speed to high. Beat until soft peaks form. Gradually beat in 1/4 cup of the sugar and beat until stiff peaks form. Set aside.
3. In another large bowl, beat the egg yolks with the cocoa and the remaining 1/2 cup sugar on high speed until the mixture forms a thick ribbon, about 2 minutes. Stir about 1/4 of the white into the yolk mixture, then fold in the remaining whites. Scrape into the prepared pan and spread evenly.
4. Bake until the cake springs back when pressed in the center, 12 to 15 minutes. Cool completely in the pan on a wire cake rack. Sift the remaining 2 tablespoons cocoa over the top of the roll. Place a large sheet of aluminum foil over the cake. Place a baking sheet over the pan. Invert the cake onto the foil. Carefully peel off the waxed paper. Cool completely.
5. To make the filling, in a small bowl, sprinkle the gelatin over the boiling water. Let stand for 10 minutes to soften the gelatin. In a small saucepan over medium-low heat, heat 1/4 cup of the cream just until warm. Add to the softened gelatin, whisk to dissolve the gelatin, and cool 10 minutes. In a chilled medium bowl, beat the remaining 1 1/4 cups cream, confectioners’ sugar, zest, and vanilla just until stiff. Beat in the gelatin mixture.
6. Spread the cake with the filling, leaving a 1-inch border. Using the foil as an aide, roll up the cake from a long end into a tight cylinder. Transfer the roll to a long platter, seam side down. Cover tightly and refrigerate until filling sets, about 1 hour or overnight.
7. To make the ganache, in a medium saucepan, bring the heavy cream to a simmer over medium-high heat. Remove from the heat and add the chocolate, corn syrup, and Grand Marnier. Let stand until the chocolate melts, about 5 minutes. Whisk until smooth and transfer to a medium bowl placed in a larger bowl of iced water. Let stand, stirring often, until chilled and thick, about 5 minutes. Whisk just until soft peaks form. Do not overwhisk. Immediately spread the ganache over the roll. Using the tines of fork, make wavy lines in the ganache to simulate bark. (The roll can be prepared up to 1 day ahead, tented with aluminum foil and refrigerated.)
8. To serve, tuck the greens under the roll. Sift the cocoa over all. Serve chilled or at cool room temperature.
Variation: For Black Forest Bûche de Noël, make a few simple changes. In the filling, delete the orange zest. Dissolve the gelatin in 1 tablespoon boiling water, then add 1 tablespoon kirschwasser or another cherry liqueur. Before rolling up the chocolate roulade, sprinkle the cream filling with 1/2 cup drained, dried, and coarsely chopped sweet cherries (or use thawed frozen cherries). Substitute kirschwasser for the Grand Marnier in the ganache.
Photo by Ben Fink