Big Chocolate Cake Recipe

Prepare and preheat

Preheat oven to 350°F (175°C). Grease and line three 9-inch round cake pans (or two 9-inch pans for taller layers) with parchment. Lightly dust with cocoa or flour; set aside.

Dry ingredients

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

Wet ingredients

In a separate bowl, whisk the eggs until blended. Add the milk, vegetable oil and vanilla; whisk to combine.

Combine batter

Add the wet mixture to the dry ingredients and mix on low speed or stir until most dry streaks disappear. Gradually add the hot water (or hot coffee) while stirring — the batter will be thin. Mix just until smooth and homogeneous.

Bake

Divide the batter evenly among prepared pans. Bake in the preheated oven 25–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (time depends on pan depth). Rotate pans halfway through baking for even color.

Cool

Allow cakes to cool in pans for 10–15 minutes, then invert onto wire racks. Cool completely (at least 1 hour) before trimming and assembling. Reserve trimmed cake pieces for cake chunk garnish.

Melt chocolate with cream (ganache base)

Place the finely chopped chocolate in a heatproof bowl. Heat the heavy cream in a small saucepan until it just simmers (do not boil). Pour the hot cream over the chocolate and let sit 2 minutes. Stir gently until smooth and glossy. If using corn syrup, stir it in now. Let the ganache cool to room temperature, stirring occasionally.

Make buttercream-finished filling

In a stand mixer fitted with the paddle (or using a hand mixer), beat the softened butter on medium speed until pale and fluffy, about 3–4 minutes. With mixer on low, gradually add the confectioners' sugar until incorporated. Add the cooled ganache to the butter mixture in two additions, mixing medium speed until smooth and silky (3–5 minutes). Add the vanilla and salt; taste and adjust sweetness or salt as desired. If filling is too soft to pipe, chill 15–20 minutes and re-whip briefly before using.

Crumble the reserved cake trimmings into rough 1/2- to 1-inch chunks. Place melted chocolate in a shallow bowl. Dip half of the cake chunks briefly into the melted chocolate and set on parchment to set, or drizzle melted chocolate over the chunks. Chill briefly to firm the chocolate if needed.

Make simple syrup: combine equal parts sugar and water in a small saucepan (or microwave-safe bowl) and heat until the sugar dissolves. Cool, then stir in espresso or coffee. Lightly brush each cake layer with simple syrup to add moisture and flavor.

Assemble the cake: If layers are uneven, level them with a serrated knife. Place one cake layer on a cake board or serving plate. Brush with simple syrup. Spread about 1 1/2 cups of the silky chocolate filling evenly over the layer (or as desired). Press a handful of cake chunks into the filling at the outer ring for texture if you like. Add the next layer, repeat brushing and filling. Top with final layer and apply a thin crumb coat of filling over entire cake; chill 15–20 minutes to set.

Finish and decorate: Apply a final generous layer of the silkiest chocolate filling, smoothing with an offset spatula. Press additional cake chunks along the top center and sides, piling them high as desired. Chill briefly to set the frosting (10–20 minutes). For a glossy finish, warm remaining melted chocolate and drizzle over the top stacks of cake chunks.

Slice and serve: Remove cake from refrigerator 20–30 minutes before serving to soften slightly for the best texture. Use a hot, clean knife (dip in hot water and wipe dry between cuts) to slice neat pieces.