Case Mountain Chocolate Cake Recipe

Prep

Preheat the oven to 350°F (175°C). Grease two 8-inch round cake pans with butter or nonstick spray, then dust with cocoa powder, tapping out excess.

Dry ingredients

In a large bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking powder, baking soda, and fine salt until evenly combined and aerated.

Wet ingredients

In a separate bowl or large measuring cup, whisk the eggs lightly, then add the whole milk, vegetable oil, and vanilla extract and whisk until blended.

Combine batter

Add the wet mixture to the dry ingredients and mix just until combined using a sturdy spatula or mixer on low speed. Scrape the bowl so there are no dry pockets.

Add boiling water

Carefully pour in the boiling water and whisk or mix on low until the batter is smooth and thin. The batter will be more liquid than typical — this yields a moist cake.

Bake

Divide the batter evenly between the prepared pans. Bake in the preheated oven for 28–34 minutes, rotating pans once halfway through. A toothpick inserted into the center should come out with a few moist crumbs but not raw batter.

Cool

Allow the cakes to cool in the pans on a wire rack for 10–15 minutes. Run a knife around the edges, invert onto the rack, remove parchment (if used), and cool completely before filling and frosting (about 1–2 hours).

Place the chopped semisweet chocolate in a heatproof bowl. Warm the heavy cream in a small saucepan over medium heat until it begins to simmer and small bubbles form at the edges; do not boil.

Pour the hot cream over the chocolate and let sit undisturbed for 1–2 minutes to soften. Add the butter and corn syrup (if using), then stir gently from the center outward until the ganache is smooth and glossy.

Let the ganache cool at room temperature, stirring occasionally, until it thickens to a spreadable consistency (about 20–30 minutes). To speed cooling, place the bowl in the refrigerator and stir every 5 minutes, taking care not to let it harden completely.

Prepare a double boiler: bring 1–2 inches of water to a simmer in a medium saucepan. In a heatproof bowl that will sit over the saucepan without touching the water, combine the egg whites and 3/4 cup granulated sugar. Whisk constantly until the mixture reaches 160°F (71°C) on an instant-read thermometer or the sugar is fully dissolved and the mixture is warm and glossy (about 3–5 minutes).

Remove the bowl from heat. Using a stand mixer fitted with the whisk attachment or a hand mixer, whip the warm egg white mixture on medium-high speed until it holds glossy stiff peaks and the bowl is cool to the touch (8–10 minutes).

With the mixer on medium speed, add the softened butter a few tablespoons at a time. The mixture may look separated at times—keep mixing and it will come together into a smooth buttercream after all butter is incorporated (4–6 minutes).

Fold in the melted semisweet chocolate (cooled but still pourable), vanilla extract, and 1/4 tsp fine salt. Mix on low to combine, then increase speed briefly to smooth the frosting. Taste and adjust salt if needed.

If the frosting is too soft, chill it briefly (10–15 minutes) and rewhip on low until spreadable. If too firm, let it come to room temperature and beat briefly.

Level the cooled cake layers if the tops domed during baking: place a serrated knife or cake leveler across the top and trim to create flat discs.

Place one cake layer on a cake board or serving plate. Spoon the cooled, spreadable ganache onto the center and use an offset spatula to spread it evenly to within about 1/2 inch of the edge to create a ganache 'mountain' core.

Top with the second cake layer, pressing gently to even the layers. Apply a thin crumb coat of the chocolate buttercream all over the cake to seal in crumbs. Chill the cake in the refrigerator for 15–20 minutes to set the crumb coat.

Apply a final generous layer of chocolate buttercream, smoothing with an offset spatula. Create peaks or waves on the top surface to mimic 'mountain' contours if desired.

Optional: press chocolate shavings or curls around the sides or on top for texture. Return the finished cake to the refrigerator for 10–15 minutes to set the frosting before slicing.

Bring slices to room temperature before serving for best flavor (about 20 minutes). Store any leftovers covered in the refrigerator for up to 4 days; bring to room temperature before eating.