Bittersweet Chocolate Roulade or Yule Log
- Espresso-Mascarpone Cream
- 3/4 cup heavy cream
- 2 tablespoons unsalted butter
- 6 ounces semisweet chocolate or bittersweet chocolate (high-quality), chopped
- 1 tablespoon Cognac
- 1/2 cup heavy cream
- 2 teaspoons espresso powder
- 6 tablespoons confectioners' sugar (1 1/2 ounces)
- 16 ounces mascarpone cheese (about 2 cups)
- 1/4 cup unbleached all-purpose flour (about 1 1/4 ounces), plus more for dusting baking sheet
- 6 ounces bittersweet chocolate or semisweet chocolate, chopped fine
- 2 tablespoons cold unsalted butter , cut into two pieces
- 2 tablespoons cold water
- 1/4 cup cocoa (3/4 ounce), Dutch-processed, sifted, plus more for unmolding and garnish
- 1/8 teaspoon table salt
- 6 large eggs , separated, room temperature
- 1/3 cup granulated sugar (2 1/3 ounces)
- 1 teaspoon vanilla extract
- 1/8 teaspoon cream of tartar
1. For Dark Chocolate Ganache: Microwave cream and butter in measuring cup on high until bubbling, about 1 1/2 minutes. (Alternatively, bring to simmer in small saucepan over medium-high heat.) Place chocolate in bowl of food processor fitted with steel blade. With machine running, gradually add hot cream and cognac through feed tube and process until smooth and thickened, about 3 minutes. Transfer ganache to medium bowl and let stand at room temperature 1 hour, until spreadable (ganache should have consistency of soft icing).
2. For Espresso-Mascarpone Cream: Bring cream to simmer in small saucepan over high heat. Remove from heat and stir in espresso and confectioners’ sugar; cool slightly. With rubber spatula, beat mascarpone in medium bowl until softened. Gently whisk in cooled cream mixture until combined. Cover with plastic wrap and refrigerate until ready to use.
3. For Roulade: Adjust oven rack to upper-middle position and heat oven to 400 degrees. Spray 18 by 12-inch rimmed baking sheet with nonstick cooking spray, cover pan bottom with parchment paper and spray parchment with nonstick cooking spray; dust baking sheet with flour, tapping out excess.
4. Bring 2 inches of water to simmer in small saucepan over medium heat. Combine chocolate, butter, and water in small heatproof bowl and cover tightly with plastic wrap. Set bowl over pan, reduce heat to medium-low, and heat until butter is almost completely melted and chocolate pieces are glossy, have lost definition, and are fully melted around edges, about 15 minutes. (Do not stir or let water in saucepan come to boil.) Remove bowl from heat, unwrap, and stir until smooth and glossy. While chocolate is melting, sift cocoa, flour, and salt together into small bowl and set aside.
5. In bowl of standing mixer, beat egg yolks at medium-high speed until just combined, about 15 seconds. With mixer running, add half of sugar. Continue to beat, scraping down sides of bowl as necessary until yolks are pale yellow and mixture falls in thick ribbon when beaters are lifted, about 8 minutes. Add vanilla and beat to combine, scraping down bowl once, about 30 seconds. Turn mixture into medium bowl; wash mixer bowl and beaters and dry with kitchen towel. (If you have 2 mixer bowls, leave yolk mixture in mixer bowl; wash and dry beaters and use second bowl in step 6.)
6. In clean bowl with clean beaters, beat egg whites and cream of tartar at medium speed until foamy, about 30 seconds. With mixer running, add about 1 teaspoon of remaining sugar; continue beating until soft peaks form, about 40 seconds. Gradually add remaining sugar and beat until whites are glossy and supple and hold stiff peaks when whisk is lifted, about 1 minute longer. Do not overbeat (if whites look dry and granular, they are overbeaten). While whites are beating, stir chocolate mixture into yolks. With rubber spatula, stir quarter of whites into chocolate mixture to lighten it. Fold in remaining whites until almost no streaks remain. Sprinkle dry ingredients over egg and chocolate mixture and fold in quickly but gently.
7. Pour batter into prepared pan; using offset icing spatula and working quickly, smooth surface and spread batter into pan corners. Bake until center of cake springs back when touched with finger, 8 to 10 minutes, rotating pan halfway through baking time. Cool cake in pan on wire rack for 5 minutes.
8. While cake is cooling, lay clean kitchen towel over work surface and sift 1 tablespoon cocoa over towel; with your hands, rub cocoa into towel. Run paring knife around perimeter of baking sheet to loosen cake. Invert cake onto towel and peel off parchment.
9. For finished cake: Starting at a long side, roll cake and towel together into jelly roll shape (see illustrations below). Cool for 15 minutes, then unroll cake and towel. Using offset spatula, immediately spread mascarpone cream filling evenly over surface of cake, almost to edges. Reroll cake gently but snugly around filling. Set large sheet of parchment paper on overturned rimmed baking sheet and set cake seam-side down on top. Trim both ends of cake on diagonal. Reserve 1/4 cup of ganache for attaching meringue mushrooms, (see related recipe). Spread ganache over roulade with small icing spatula. Use fork to make wood-grain striations on surface of ganache before it has set. Refrigerate cake, uncovered, on baking sheet to slightly set icing, about 20 minutes.
10. When ready to serve, carefully slide 2 wide metal spatulas under cake and transfer cake to serving platter. Arrange meringue mushrooms around cake, attaching them with dabs of reserved ganache. Sift light dusting of cocoa over mushrooms. Sift yule log with confectioners’ sugar. Serve within 2 hours.