Prepare the Cake Pans: Preheat the oven to 350°F (177°C). Grease three 9-inch round cake pans, line the bottoms with parchment paper rounds, and grease the parchment paper. This preparation helps the baked cakes release cleanly.
Combine the Dry Ingredients: In a large mixing bowl, whisk together the flour, cocoa powder, granulated sugar, baking soda, baking powder, salt, and optional espresso powder until evenly distributed. Set aside.
Mix the Wet Ingredients: Using a stand mixer fitted with a flat beater, beat the oil, room-temperature eggs, sour cream, buttermilk, and vanilla extract until thoroughly combined.
Prepare the Chocolate Batter: Add the dry ingredients to the wet mixture. Pour in the hot water or hot coffee, then mix until the batter is smooth and all the ingredients are fully incorporated.
Divide the Batter: Distribute the batter evenly among the three prepared cake pans, keeping the amounts as equal as possible so the layers bake consistently.
Bake the Cake Layers: Bake at 350°F (177°C) for 21–25 minutes. Check the centers with a toothpick; the cakes are ready when it comes out clean. Baking time may vary, so monitor them closely.
Cool the Cakes: Transfer the pans to a wire rack and let the cakes cool for 30 minutes in their pans. Carefully remove the layers and place them directly on the cooling rack, handling them with both hands to prevent breakage.
Level the Cake Layers: Once the cakes have cooled completely, use a large serrated knife or cake leveler to trim a thin layer from the top of each cake, creating flat, even surfaces. Discard the trimmings or crumble them over ice cream.
Prepare the Cherry Syrup: Drain the canned cherries, reserving ¾ cup (180 ml) of the heavy syrup. Set the cherries aside. Combine the reserved syrup with the cherry liqueur in a small saucepan. Simmer over low heat until the mixture reduces to approximately ¼ cup (60 ml). Brush the reduced syrup over the cooled cake layers, reserving any remaining syrup for assembly. Prepare the Cherries: Cut the drained cherries in half. Reserve a few whole cherries for decorating the finished cake, and set the halved cherries aside for the filling.
Make the Chocolate Ganache: Place the finely chopped semi-sweet chocolate in a medium bowl and add the optional light corn syrup. Heat the heavy cream in a small saucepan until it begins to gently simmer; do not allow it to reach a rapid boil. Pour the hot cream over the chocolate and leave it undisturbed for 2–3 minutes. Stir slowly until the chocolate melts completely and the mixture becomes smooth. Let the ganache cool for 10 minutes while preparing the whipped cream. Whip the Cream: Using a stand mixer fitted with a whisk attachment, beat the cold heavy cream, confectioners’ sugar, and vanilla extract on medium-high speed for about 4 minutes, or until medium peaks form. The cream should hold its shape, with the tips gently curling when the whisk is lifted. Assemble the First Layer: Place one chocolate cake layer on a cake stand, turntable, or serving plate. Spread 1 heaping cup of whipped cream evenly over the surface. Scatter half of the halved cherries on top and drizzle with a spoonful of the reserved reduced cherry syrup. Add the Second Layer: Place the second cake layer over the filling. Spread another heaping cup of whipped cream across the top, add the remaining halved cherries, and drizzle with another spoonful of cherry syrup.
Finish the Cake Layers: Position the third cake layer on top. Spread the remaining whipped cream over the top and sides of the cake in a thin, even coating using an icing spatula. Smooth the sides with a bench scraper for a neat finish.
Apply the Ganache: Pour the cooled chocolate ganache over the top of the assembled cake. Gently spread it toward the edges, allowing some ganache to drip naturally down the sides. Decorate the top with the reserved whole cherries.
Chill Before Serving: Refrigerate the assembled cake for at least 30 minutes before slicing and serving. This chilling time helps the layers and toppings settle.
Store Leftovers: Cover the remaining cake and store it at room temperature for up to 1 day or in the refrigerator for up to 1 week.
