Preston's Chocolate Fudge Cake Recipe

Prepare

Preheat oven to 350°F (175°C). Grease and line five 8-inch round cake pans (or use three pans and bake in batches). If you only have fewer pans, divide batter and bake in batches; pans should be well buttered and bottom-lined with parchment.

Dry ingredients

In a large bowl, sift or whisk together 3.5 cups all-purpose flour, 3 cups granulated sugar, 1.25 cups cocoa powder, 2 tsp baking powder, 2 tsp baking soda, and 2 tsp salt until uniform.

Wet ingredients

In a separate bowl, whisk 4 large eggs lightly. Add 2 cups buttermilk, 0.5 cup whole milk, 1 cup vegetable oil, and 2 tsp vanilla; whisk until combined.

Combine batter

With the mixer on low speed, add the wet mixture to the dry ingredients in two additions, mixing until just combined and no large dry streaks remain. Scrape the bowl. Slowly add 1 cup hot brewed coffee while mixing on low; batter will be thin — this gives extra moistness and deep chocolate flavor.

Divide and bake

Divide batter evenly among the five prepared 8-inch pans (use kitchen scale for consistency; each should have roughly the same amount). Smooth tops. Bake at 350°F (175°C) for 18–24 minutes, rotating pans halfway, until a toothpick inserted in the center comes out with a few moist crumbs and tops spring back. If baking in batches, keep baked layers wrapped in plastic while remaining layers bake to retain moisture.

Cool

Remove cakes to wire racks and let cool in pans for 10 minutes. Run a knife around edges, invert onto racks, remove parchment, and cool completely (about 1 hour) before assembling. If layers dome slightly, trim level with a serrated knife.

Melt chocolate and butter

Place 1 cup (2 sticks) unsalted butter and 10 oz chopped semisweet chocolate in a heatproof bowl set over barely simmering water (double boiler), making sure bowl doesn't touch water. Stir until smooth and fully melted. Alternatively, microwave in 20–30 second bursts, stirring between, until melted.

Add cocoa and cream

Remove bowl from heat. Whisk in 0.75 cup unsweetened cocoa powder until smooth. Stir in 1 cup heavy cream and 2 tbsp light corn syrup until combined — mixture will be glossy and pourable.

Incorporate sugar and season

Gradually whisk in 6 cups powdered sugar, about 1 cup at a time, until you reach a thick but spreadable consistency. Add 2 tsp vanilla and 1/2 tsp fine sea salt. If icing is too stiff, add more cream 1 tbsp at a time; if too thin, add more powdered sugar 1/4 cup at a time. Let icing cool slightly until it thickens enough to spread but is still workable (15–25 minutes).

Prepare layers

If using, warm 1/2 cup simple syrup (or reserved coffee) and brush a light coat on each cake layer to enhance moistness. Put a small amount of softened butter (2 tbsp) on cake board or serving plate to anchor the first layer.

Stack and fill

Place first cake layer on the board. Spread a generous, even layer (about 3/4 to 1 cup) of chocolate fudge icing over the top, leaving about 1/4 inch from the edge. Repeat with remaining layers, stacking carefully so edges align. Reserve ~1.5–2 cups frosting for topping and sides.

Crumb coat

Apply a thin coat of icing around the top and sides to catch crumbs. Chill the assembled cake in the refrigerator for 20–30 minutes to set the crumb coat.

Final coat and decoration

Apply the remaining icing in a thicker, even coat over the top and sides using an offset spatula. Smooth or create swirls as desired. Press optional chocolate shavings or sprinkles onto the sides or top. Allow the cake to rest at room temperature for 30–60 minutes to let icing set before slicing.

Serve

Slice with a clean, warm knife (dip in hot water and wipe dry between cuts for clean slices). Store leftover cake tightly covered at room temperature for up to 2 days or refrigerate for up to 5 days (bring to room temperature before serving).