Cake
2¾ cups cake flour
1 cup natural unsweetened cocoa powder
2 teaspoons baking soda
¾ teaspoon salt
½ teaspoon baking powder
2¾ cups sugar
4 large eggs
2 large egg yolks
1 cup vegetable oil
1 cup sour cream
1 tablespoon vanilla extract
¾ cup mini semisweet chocolate chips
Ganache
3 cups heavy whipping cream
1½ pounds bittersweet or semisweet chocolate (do not exceed 61% cacao), chopped
Mousse
4⅓ cups chilled heavy whipping cream, divided
½ cup light corn syrup
1¼ pounds bittersweet or semisweet chocolate (do not exceed 61% cacao), chopped
Assembly and Serving
⅔ cup seedless raspberry jam
1 15¾×11¾-inch transfer sheet with gold-thread design
¾ pound bittersweet or semisweet chocolate, chopped
3½-pint containers raspberries
½ pound cherries
1 1-pint container small strawberries
1½-pint container blueberries
1½-pint container blackberries
Decorating Made EasyPliable plastic sheets called transfers are coated with a mixture of cocoa butter and food coloring and etched with repetitive designs. The ones used here create an exquisite gold-thread pattern on the band of chocolate that’s wrapped around the cake. The sheets are see-through, so be sure the pattern side is facing up (you can tell by touching the raised surface with your fingertips). They’re easy to use, too; the melted chocolate is simply spread over the sheets, and once the chocolate becomes firm, the plastic sheets are peeled away, leaving an edible design on the chocolate’s surface. You can purchase transfer sheets at some cake and candy supply stores or by mail from Beryl’s Cake Decorating & Pastry Supplies (beryls.com or 800-488-2749).
CAKE: Position rack in center of oven and preheat to 350°F. Butter and flour two 10-inch-diameter cake pans with 2-inch-high sides; line each with round of parchment paper or waxed paper. Combine flour, cocoa, baking soda, salt, and baking powder in medium bowl; whisk to blend well. Using electric mixer, beat sugar, eggs, and egg yolks in large bowl until very thick and heavy ribbon falls when beaters are lifted, about 6 minutes. Add oil, sour cream, and vanilla, then flour mixture all at once to egg mixture. Beat at low speed until just blended, about 1 minute. Scrape down sides of bowl. Beat at high speed until well blended, about 3 minutes. Fold in chocolate chips; divide batter between prepared pans (about 3¾ cups batter in each).
Bake cakes until tester inserted into center comes out clean, about 40 minutes. Cool cakes completely in pans on racks. Cover and let cakes stand at room temperature overnight.
GANACHE: Bring cream to simmer in heavy large saucepan over medium-high heat. Remove from heat. Add chocolate and whisk until chocolate is melted and mixture is smooth. Transfer ganache to glass bowl. Let stand until thick enough to spread, about 4 hours.
DO AHEAD: Can be made 1 day ahead. Cover; chill.
MOUSSE: Using electric mixer, beat 3⅓ cups cream in large bowl until peaks form; chill. Combine remaining 1 cup cream and corn syrup in heavy medium saucepan and bring to simmer. Remove from heat. Add chocolate and whisk until melted, smooth, and still warm to touch. Pour warm chocolate mixture directly onto whipped cream and fold in gently. Chill until mousse is set, at least 8 hours.
DO AHEAD: Can be made 1 day ahead. Cover and keep chilled.
ASSEMBLY AND SERVING: Cut around pan sides; turn out cakes. Peel off parchment. Cut each cake horizontally in half. Place 1 cake layer, cut side up, on 9-inch-diameter tart pan bottom or cardboard round. Place another cake layer, cut side up, on clean baking sheet. Spread each with ⅓ cup raspberry jam. Chill until jam sets, about 15 minutes.
If ganache is chilled, microwave on defrost setting in 15-second intervals until just soft enough to spread, stirring occasionally. Drop 1 cup ganache by rounded teaspoonfuls over each jam layer. Using offset spatula, gently spread ganache to cover jam. Drop 3 cups mousse by heaping spoonfuls onto each ganache layer; gently spread to cover. Chill cake layers 30 minutes. Using large metal spatula, place cake layer from baking sheet, mousse side up, atop cake layer on tart pan bottom. Place third cake layer, cut side down, atop cake (reserve remaining cake layer for another use). Spread 1 cup mousse over top of assembled cake. Using long offset spatula, spread sides of assembled cake with enough ganache (about 1½ cups) to fill gaps and make smooth surface. Transfer cake on tart pan bottom to platter.
Turn 1 large baking sheet upside down on work surface. Arrange two 20-inch-long pieces of foil on work surface. Cut two 15¾×4½-inch-strips from transfer sheet. Lay 1 transfer sheet strip, rough-textured design facing up, onto each sheet of foil.
Place chocolate in medium metal bowl; set bowl over saucepan of simmering water (do not allow bowl to touch water). Stir until chocolate is smooth and very warm to touch (about 115°F). Remove bowl from over water.
Pour thick ribbon of melted chocolate (about ⅔ cup) onto 1 transfer sheet strip. Using long offset spatula, spread chocolate evenly over transfer strip, covering completely (chocolate will run over sides of strip) [1]. Using tip of knife, lift edge of chocolate-coated strip. Slide hands between transfer strip and foil; lift entire transfer strip and place it, chocolate side up, on inverted baking sheet [2]. Chill until chocolate on strip is set and loses gloss but is still flexible (do not let chocolate become too firm), about 1½ minutes. Using fingertips, lift chocolate-coated strip and attach, chocolate side in, to side of cake [3]. Press strip to seal chocolate to side of cake (strip will stand about 1 inch above top edge of cake). Coat remaining transfer strip with chocolate and transfer to inverted baking sheet; chill until set but still flexible. Arrange 1 end of second strip against (but not overlapping) 1 end of first strip. Press second strip to seal chocolate to side of cake (both strips will just encircle cake). Chill cake until chocolate strips are firm, about 30 minutes. Carefully peel transfer paper off chocolate strips [4]. Chill cake at least 3 hours and up to 1 day.
Mound fruit atop cake. Chill until ready to serve.
DO AHEAD: Cake can be assembled up to 8 hours ahead. Keep chilled.
Adorned with a ribbon and a big bow, this cake looks like a delicious present. Adding corn syrup to the melted chocolates creates a pliable mixture known as modeling chocolate. Using a pasta machine makes it easy to roll out sheets of chocolate to cut into ribbons, but the cake would look stunning with just the glaze and fresh flowers. 12 to 14 servings
Cake
1½ cups (3 sticks) butter, room temperature
2 cups sugar
8 eggs, separated, room temperature