Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch pan. In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt. In a separate bowl, mix eggs, buttermilk, oil, and vanilla. Add wet ingredients to the dry and mix until just combined. Stir in hot coffee. Pour batter into the prepared pan.

Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool completely on a wire rack. Once cooled, cut the cake into 1-inch cubes.

In a medium saucepan, combine the cherries, sugar, and a slurry made from the cornstarch and a few tablespoons of water or reserved cherry juice. Cook over medium heat, stirring constantly, until the mixture has thickened, about 5-7 minutes. Remove from heat and stir in the Kirsch. Let it cool completely.

In a large bowl using a stand or hand mixer, beat the cold heavy cream, powdered sugar, and vanilla extract on high speed until stiff peaks form.

In a large trifle bowl, layer half of the cake cubes, followed by half of the cooled cherry filling, and then half of the whipped cream. Repeat the layers. Garnish the top layer of cream with chocolate shavings and fresh cherries.

Cover and refrigerate for at least 4 hours before serving to allow the flavors to meld. Garnish just before serving for the best appearance.