1. Prepare the Cake Layers: A Rich and Moist Chocolate Base

 

Preheat and Prep Pans: Preheat the oven to 350°F (175°C). Butter two 8-inch round cake pans and line the bottoms with parchment paper circles. Grease the parchment paper as well. This ensures the cakes will release cleanly.

 

Whisk Dry Ingredients: In a large bowl, whisk together the all-purpose flour, granulated sugar, Dutch-process cocoa powder, baking soda, baking powder, and salt until well combined.

 

Combine Wet Ingredients (Except Coffee): In a separate medium bowl, whisk together the buttermilk, vegetable oil, eggs, and vanilla extract until smooth.

 

Gradually Add Wet to Dry: Slowly add the wet ingredients to the dry ingredients, mixing on low speed with an electric mixer or stirring with a rubber spatula until just combined. Do not overmix.

 

Incorporate Hot Coffee: Gradually add the hot brewed coffee to the batter, mixing on low speed until just combined. The batter will be thin, which is normal for this recipe.

 

Prepare for Crumb Topping: Fill 2 cupcake papers with the batter, and set aside. This will be used for the crumb topping.

 

Divide and Bake: Divide the remaining batter evenly between the two prepared 8-inch cake pans. Bake for 35 minutes, or until a wooden skewer inserted into the center comes out clean or with a few moist crumbs attached.

 

Bake Cupcakes: When the cake layers come out of the oven, place the cupcakes in and bake for 15 minutes, or until the top springs back and a toothpick comes out clean.

 

Cool: Let the cake layers cool in the pans for about 10 minutes before inverting them onto a wire rack to cool completely. Let the cupcakes cool completely.

 

2. Make the Pudding Filling: A Creamy Chocolate Center

 

Combine Cocoa and Boiling Liquid: While the cake layers are baking, make the pudding filling. In a medium saucepan, whisk together the 2 tablespoons of Dutch-process cocoa powder with 1 cup of boiling water or hot brewed coffee until the cocoa is fully dissolved.

 

Add Sugar, Chocolate, and Salt: Stir in the 6 tablespoons of sugar, 1 ounce of chopped bittersweet chocolate, and ¼ teaspoon of salt.

 

Make Cornstarch Slurry: In a small bowl, whisk together 2 tablespoons of cornstarch with 2 tablespoons of cold water until smooth. This forms a slurry, which will thicken the pudding.

 

Thicken Pudding: Whisk the cornstarch slurry directly into the saucepan with the cocoa mixture. Bring the mixture to a boil over medium heat, stirring constantly.

 

Boil: Boil for one minute, stirring continuously, until the pudding thickens.

 

Add Vanilla and Butter: Remove the pan from the heat and whisk in 1 teaspoon of vanilla extract and 1 tablespoon of butter until smooth.

 

Chill: Transfer the pudding to a bowl and cover it with plastic wrap, pressing the wrap directly onto the surface of the pudding to prevent a skin from forming. Chill in the refrigerator until completely cool and set.

 

3. Make the Frosting: A Rich and Glossy Chocolate Topping

 

Melt Butter and Chocolate: Melt the ¾ cup (1 ½ sticks) of unsalted butter and 12 ounces of finely chopped semisweet chocolate together. You can do this in the microwave (start with one minute, then stir, and add 15-second bursts, stirring in between) or in a saucepan over low heat. If using a saucepan, melt the butter first, then add the chocolate.

 

Whisk in Remaining Ingredients: Whisk in the ½ cup of hot water all at once, followed by 1 tablespoon of corn syrup and 1 tablespoon of vanilla extract. Stir until the frosting is smooth and glossy.

 

Chill: Place the bowl of frosting in the refrigerator to chill for 20-30 minutes, or until it firms up to a spreadable consistency.

 

4. Assemble the Cake: Building Layers of Decadence

 

Make Crumbs: Take the two cupcakes that were baked, and pulse them in a food processor until you have fine, even crumbs. Set aside.

 

Level Cake Layers (Optional): If the cake layers have domed tops, you can use a long, serrated knife to carefully level them by trimming off the domes. This will create a more even surface for layering.

 

Remove Parchment: Make sure you peel off the parchment paper from the bottoms of your cake layers.

 

First Layer: Place one cake layer, flattest side facing up, on a serving plate or cake stand.

 

Add Pudding: Top the first cake layer with a generous layer of the chilled chocolate pudding. You won’t need to use all of the pudding.

 

Second Layer: Carefully place the second cake layer, flat side up, on top of the pudding layer.

 

Pudding on Sides: Lightly spread more pudding along the sides of the cake. This will act as a “glue” for the crumbs.

 

Apply Crumbs: Press the reserved cake crumbs onto the pudding-coated sides of the cake with your hands. This will be a bit messy, but it’s part of the fun!

 

Frost Top: Generously frost the top of the cake with the chilled chocolate frosting.

 

Add More Crumbs (Optional): Add more crumbs to the top of the cake, either all over or just around the edges, for a decorative touch.

 

Chill: Chill the assembled cake in the refrigerator until ready to serve. This helps the frosting set and makes the cake easier to slice.