Black Forest Cake

FOR THE CAKE: Adjust oven rack to upper- and lower-middle positions; heat oven to 350 degrees. Meanwhile, grease three 8-inch cake pans with butter and line bottom of each pan with parchment paper round. Combine chocolate and cocoa in medium bowl; pour boiling water over and whisk until smooth. Sift together flours, baking soda, and salt onto large sheet of parchment or waxed paper; set aside.

Place butter in bowl of stand mixer with paddle attachment and beat at medium-high speed until creamy, about 1 minute. Add brown sugar and beat on high until light and fluffy, about 3 minutes. Stop mixer and scrape down bowl with rubber spatula. Increase speed to medium-high and add eggs one at a time, beating 30 seconds after each addition. Reduce speed to medium; add vanilla and beat until combined. Stop mixer and scrape down bowl. With mixer on low, add about one third of flour mixture, followed by about one half of chocolate mixture. Repeat, ending with flour mixture; beat until just combined, about 15 seconds. Do not overbeat. Remove bowl from mixer; scrape bottom and sides of bowl with rubber spatula and mix gently to thoroughly combine.

Divide batter evenly among cake pans and smooth batter to edges of pan with rubber spatula. Place two pans on lower-middle rack and one on upper-middle rack. Bake until toothpick inserted in center comes out clean, 20 to 23 minutes. Let cakes cool on wire racks for 15 to 20 minutes. Remove cakes from pans, discarding parchment, and let cool completely on racks.

Using stand mixer fitted with whisk attachment, whip remaining 2½ cups cream and vanilla on low speed until frothy, about 30 seconds. Increase speed to medium and continue to whip until mixture begins to thicken, about 30 seconds. Slowly add cooled sugar mixture and continue to whip until soft peaks form, about 1 minute.

FOR THE CHERRIES: Reserve 8 prettiest cherries for garnish in small bowl. Slice remaining cherries in half and place in second bowl. Bring reserved cherry syrup and sugar to simmer in medium saucepan over medium heat and cook until syrup is thickened and measures about ½ cup, 8 to 10 minutes. Off heat, stir in kirsch. Toss 1 tablespoon syrup with cherries reserved for garnish. Toss 3 tablespoons more syrup with halved cherries.

FOR THE WHIPPED CREAM: Whisk sugar and cornstarch together in small saucepan and slowly whisk in ½ cup cream. Bring mixture to simmer over medium heat, whisking constantly, until mixture thickens, 2 to 3 minutes. Let mixture cool completely, about 30 minutes.

Using stand mixer fitted with whisk attachment, whip remaining 2½ cups cream and vanilla on low speed until frothy, about 30 seconds. Increase speed to medium and continue to whip until mixture begins to thicken, about 30 seconds. Slowly add cooled sugar mixture and continue to whip until soft peaks form, about 1 minute.

TO FINISH: Line edges of cake platter with 4 strips of parchment paper to keep platter clean. Poke top of cake layers thoroughly with wooden skewer and brush with remaining syrup. Place 1 cake layer on platter. Spread ½ cup whipped cream over top, right to edge of cake, then cover with half of sliced cherries. Repeat with 1 more cake layer, ½ cup more whipped cream, and remaining sliced cherries. Top with remaining cake layer, pressing lightly to adhere. Spread remaining whipped cream evenly over top and sides of cake.

Refrigerate cake so it absorbs soaking syrup, at least 2 hours or up to 24 hours. Before serving, let cake sit at room temperature for 30 minutes to 1 hour, then gently press shaved chocolate into sides of cake. Evenly space 8 small piles of shaved chocolate around top of cake and top each with cherry. Carefully remove parchment strips before serving.