3/4 cup (180g) full fat sour cream, at room temperature*
1/2 cup (120ml) buttermilk, at room temperature*
2 teaspoons pure vanilla extract
1/2 cup (120ml) hot water or coffee*
2 (15 ounce) cans dark sweet cherries in heavy syrup*
2 Tablespoons cherry liquor (sold as kirsch or kirschwasser)*
1 cup (240ml) heavy cream or heavy whipping cream
two 4-ounce semi-sweet chocolate bars (226g), finely chopped
optional: 1 Tablespoon light corn syrup*
2 cups (480ml) cold heavy cream or heavy whipping cream
1/4 cup (30g) confectioners’ sugar
1 teaspoon pure vanilla extract
Preheat the oven to 350°F (177°C). Grease three 9-inch cake pans, line with parchment paper, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans.
Make the chocolate cake: Whisk the flour, cocoa powder, sugar, baking soda, baking powder, salt, and espresso powder (if using) together in a large bowl. Set aside. Using a KitchenAid stand mixer fitted with a flat beater, beat the oil, eggs, sour cream, buttermilk, and vanilla together until combined. Pour the dry ingredients into the wet ingredients, add the hot water or coffee, and beat it all until the batter is completely combined.
Divide batter evenly between 3 pans. Bake for 21-25 minutes. Baking times vary, so keep an eye on yours. The cakes are done when a toothpick inserted in the center comes out clean. Remove the cakes from the oven and set on a wire rack. Allow to cool for 30 minutes in the pans, then remove cakes from pans and set on a cooling rack. Be careful and use two hands when handling the cakes.
Drain the cherries, reserving 3/4 cup (180ml) of the heavy syrup. Set cherries aside. Simmer syrup and cherry liquor in a small saucepan over low heat until reduced down to 1/4 cup (60ml). Brush reduced syrup all over the cakes, reserving any leftover syrup. The cakes can be slightly warm when you do this.
Slice the cherries in half, leaving a few whole cherries for garnish. Set aside.
Make the ganache: Place chopped chocolate and corn syrup, if using, in a medium bowl. Heat the cream in a small saucepan until it begins to gently simmer. (Do not let it come to a rapid boil– that’s too hot!) Pour over chocolate and let it sit for 2-3 minutes to gently soften the chocolate. Slowly stir until completely combined and chocolate has melted. Set aside to cool for 10 minutes as you prepare the whipped cream.
Make the whipped cream: Using a KitchenAid stand mixer fitted with a whisk attachment, whip the heavy cream, sugar, and vanilla extract on medium-high speed until soft peaks form, about 3 minutes.
Assemble the cake: First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand, cake turntable, or serving plate. Spread 1 heaping cup of whipped cream evenly on top. Dot with half of the halved cherries and drizzle with a spoonful of reduced syrup. Top with 2nd cake layer and evenly cover the top with 1 heaping cup whipped cream, the remaining halved cherries, and another drizzle of reduced syrup. Top with the 3rd cake layer. Spread the remaining whipped cream on top and all around the sides in a thin layer using an icing spatula. Use a bench scraper to smooth out the whipped cream on the sides of the cake.
Pour chocolate ganache on top of the cake. Spread to the edges of cake allowing it to gently drip down the sides. Top with whole cherries. Refrigerate for at least 30 minutes before slicing and serving.
Cover and store leftover cake at room temperature for 1-2 days or in the refrigerator for up to 1 week.