Double Chocolate Blackout Cake Recipe

Prepare

Preheat oven to 350°F (175°C). Grease two 8-inch round cake pans and line bottoms with parchment; grease parchment and dust pans lightly with flour or cocoa powder.

Whisk together dry ingredients: in a large bowl, sift or whisk the all-purpose flour, unsweetened cocoa powder, granulated sugar, baking powder, baking soda, and fine salt until evenly combined.

Combine wet ingredients: in a separate bowl or large measuring cup, whisk the eggs, buttermilk, whole milk, neutral oil, and vanilla extract until smooth.

Mix batter: add the wet ingredients to the dry and stir just until combined. The batter will be thick. Stir in the hot water or hot coffee a little at a time until batter is smooth and slightly thin — this intensifies chocolate flavor and yields a moist crumb.

Divide and bake: divide batter evenly between prepared pans (use a kitchen scale or eye it). Smooth tops. Bake in the center of the preheated oven for 25–30 minutes or until a toothpick inserted into the center comes out with a few moist crumbs and the cake springs back when lightly pressed.

Cool: allow cakes to cool in pans on a wire rack for 10–15 minutes. Run a thin knife around the edge, invert onto racks to remove pans, then peel off parchment and let layers cool completely before filling (about 1 hour).

Heat cream: place the chopped bittersweet chocolate in a heatproof bowl. In a small saucepan, heat the heavy cream until it just begins to simmer (do not boil).

Make ganache: pour the hot cream over the chopped chocolate. Let sit 1–2 minutes to soften chocolate, then stir gently from the center outward until smooth and glossy. Add the unsalted butter and corn syrup (if using) and stir until incorporated.

Cool to spreadable consistency: let ganache cool at room temperature, stirring occasionally, until thickened but still spreadable (20–40 minutes). If you need to speed cooling, transfer to a shallow bowl and chill briefly, checking every 5 minutes.

Combine ingredients: place chopped dark chocolate, heavy cream, butter, light brown sugar, and a pinch of salt in a heatproof bowl or small saucepan.

Melt and whisk: warm gently over low heat or use a double boiler, stirring constantly until chocolate and butter are fully melted and sugar dissolved, creating a glossy sauce. Do not overheat or allow to boil.

Adjust consistency: if sauce is too thick, whisk in 1–2 tsp more warm cream. Keep sauce warm for glazing or let it cool to slightly thickened for serving alongside slices.

Make buttercream: in a stand mixer fitted with paddle or a large bowl with a hand mixer, beat the softened butter until pale and fluffy, about 2 minutes. Sift in the cocoa powder and powdered sugar in batches, alternating with the heavy cream (or milk). Beat on low to start, then medium-high until smooth and spreadable. Add vanilla and salt; taste and adjust sweetness or consistency with more cream or powdered sugar as needed.

If a very dark, intense coating is desired, fold 1–2 tablespoons of melted and cooled dark chocolate into the frosting.

Level layers: if cake tops domed, level them with a serrated knife so layers stack evenly.

Layer with ganache: place one cake layer on a serving plate or cake turntable. Spoon half the ganache onto the first layer and spread evenly to edge. Place the second layer on top and press gently.

Coat cake (two options): for a clean, decadent finish, pour some of the warm dark chocolate sauce over the top, tilting the cake so it drips slightly down the sides and covers the top with a shiny glaze. Alternatively, chill the cake 10–15 minutes to set the ganache, then crumb-coat and finish with the chocolate frosting using an offset spatula for a smooth outer coat.

Garnish: scatter coarsely chopped dark chocolate or chocolate shavings on top and dust lightly with cocoa powder if desired.

Chill and serve: chill the assembled cake 20–30 minutes so fillings set. Bring to room temperature for 20–30 minutes before serving for best texture. Serve slices with additional warmed dark chocolate sauce on the side.