Black Pearl Layer Cake

Ingredients:
6 ounces bittersweet (not unsweetened) or semisweet chocolate, chopped
3/4 cup heavy whipping cream
1 teaspoon ground ginger
1/2 teaspoon wasabi powder*
2 tablespoons black sesame seeds*
1 tablespoon corn syrup
2 tablespoons (1/4 stick) butter, room temperature
1 cup water
1/2 cup sugar
5 tablespoons matchstick-size strips peeled fresh ginger
1 vanilla bean, split lengthwise
2 cups boiling water
1 cup unsweetened cocoa powder
2 3/4 cups all purpose flour
2 teaspoons baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
2 1/4 cups sugar
1 cup (2 sticks) unsalted butter, room temperature
4 large eggs
1 tablespoon vanilla extract
2 cups chilled heavy whipping cream
1/4 cup plus 2 tablespoons powdered sugar
1/2 teaspoon vanilla extract
1/2 teaspoon ground ginger
Additional black sesame seeds

Instructions:
Place chocolate in medium bowl. Bring cream, ginger, and wasabi to boil in small pot. Pour hot cream over chocolate; cover with plastic wrap and let stand 15 minutes. Whisk cream and chocolate until smooth. Mix sesame seeds and corn syrup in small bowl to coat; stir into chocolate mixture. Let cool to lukewarm. Stir in butter. Cover and let stand at room temperature overnight to set.
Place 1 cup water, sugar, and ginger in small saucepan. Scrape seeds from vanilla bean into pan; add bean. Stir over medium heat until sugar dissolves. Simmer 2 minutes; remove from heat. Let stand at room temperature 1 hour for flavors to blend.
Strain syrup into small bowl. Chop ginger. (Can be prepared 1 day ahead. Cover and refrigerate ginger and syrup separately.)
Preheat oven to 350°F. Butter and flour three 8-inch-diameter cake pans with 2-inch-high sides. Line bottoms with parchment paper.
Whisk 2 cups boiling water, cocoa powder, and reserved chopped ginger in medium heatproof bowl. Whisk flour, baking soda, baking powder, and salt in large bowl. Using electric mixer, beat sugar and butter in large bowl until fluffy, about 1 minute. Add eggs 1 at a time, beating until incorporated after each addition. Beat in vanilla extract. Add flour mixture in 4 additions alternately with cocoa mixture in 3 additions, beginning and ending with flour mixture. Divide batter among prepared cake pans; smooth tops.
Bake cakes until tester inserted into center comes out clean, about 30 minutes. Cool in pans 5 minutes. Turn cakes out onto racks; cool completely. (Cakes can be prepared 1 day ahead. Wrap with plastic wrap and store at room temperature.)
Beat cream in large bowl until soft peaks form. Add sugar, vanilla, and ginger. Beat until stiff peaks form.
Using long serrated knife, trim rounded tops off cakes to create flat surface. Place 1 cake layer, cut side up, on plate. Brush top with 1/3 cup ginger syrup. Spread half of ganache over top of cake. Place second layer, cut side up, atop first layer. Brush with 1/3 cup syrup; spread with remaining ganache. Top with third cake layer. Brush with remaining syrup. Spread sides and top with whipped cream frosting. Sprinkle top with black sesame seeds. Refrigerate until ganache is set, about 4 hours. Let stand at room temperature 30 minutes before serving. (Can be made 1 day ahead. Keep refrigerated.)
*Available in the Asian foods section of some supermarkets and at Asian markets.