THREE 6" rounds or TWO 8" rounds

    • 180g (1 1/2 c.) AP flour
    • 300g (1 1/2 c.) white sugar
    • 55g dutch-process cocoa powder sifted
    • 10g black cocoa powder sifted
    • 1 1/2 tsp baking soda
    • t tsp baking powder
    • 1 tsp salt
    • 60g (1/4 c.) vegetable oil
    • 180g (3/4 c.) buttermilk room temp
    • 3/4 cup hot water
    • 2 eggs room temp
    • 2 tsp vanilla


    • 115g (1 stick) unsalted butter
    • 300g (1 1/2 c.) white sugar
    • 130g dutch cocoa powder sifted
    • 20g black cocoa powder sifted
    • pinch of salt
    • 180ml/g (3/4 c.) heavy whipping cream
    • 120ml/g (1/2 c.) sour cream
    • 2 tsp vanilla



    • Butter baking pans and dust with cocoa powder. Line bottoms with a circle of parchment.
    • Place all dry ingredients into the bowl of a stand mixer fitted with a paddle attachment. Sift in flour and cocoa powder. 
    • In a separate bowl, whisk to combine all remaining wet ingredients; set aside.
    • Begin stand mixer on a stir-speed with just your dry ingredients to fully combine. 
    • Add wet ingredients and increase to medium speed for 2-3 mins. Batter will be very thin.
    • Portion evenly between your cake pans. Bake at 350°F 22-28mins for 6inch; 30-35 for 9inch. Bake until a cake tester comes out mostly clean. Not wet, some damp crumbs.
    • Once cool enough to handle, turn out cakes, peel off parchment, and double wrap in saran wrap. Freeze until ready to frost.
    • Optional: Before wrapping with saran wrap, you can apply a cake soak for an extra-moist cake. Combine some sugar and milk or heavy cream and brush over the cake, allowing it to soak in.


    • In a bowl, combine cream and sour cream. Whisk to combine; set aside.
    • In a separate bowl, combine sugar, salt, and sift in cocoa powders; set aside. 
    • Melt butter in a saucepan over medium heat.
    • Once melted, add dry ingredients and mix with a spatula until fully combined. The mixture will be very thick, clumpy, dry and grainy.
    • Add the wet ingredients and whisk frequently/continuously for about 5 minutes – until sugar is fully dissolved. Keep the flame over medium/low. Do not allow the mixture to bubble or boil. Use a spatula to make sure nothing is sticking to the bottom.
    • Remove from the heat, transfer to a heat-proof bowl and whisk in the vanilla. Cover with cling wrap pressed against the top of the frosting and refrigerate for 3-4 hours minimum, or overnight – until thickened enough to spread. 


    • Assemble the cake using your cake layers and frosting straight out of the freezer & fridge. Frosting is very thick and sticky. Use an offset spatula or knife to frost in an old-fashioned manner. Do not expect clean frosting lines. If frosting is too difficult to work with, let it sit at room temp to soften up a bit. Keep frosted cake refrigerated until a few hours before serving.
      Keep cake out of the sun & heat.
    This recipe will make three 6″ rounds or two 8″ rounds.
    For two 9″ rounds, multiply both the cake and frosting recipe by 1.5x

    Important tips:

    This cake is very delicate and the frosting is very thick. I recommend you freeze your cake layers before frosting, otherwise your cake will be sticking to the frosting and falling apart. Personally, I find it makes everything easier to make the cake and frosting at least a day in advance and simply assemble the day you need it.

    When I make this cake, I’m not particular about how much black cocoa powder I use. I measure out the total dutch + black cocoa powder needed: going most of the way with the dutch-process cocoa powder and leaving the last handful of grams for the black cocoa powder. A little goes a long way for darkening up your cake and frosting. I think this makes all the math easier when I increase the recipe size.

    I recommend baking this cake as 2 layers. The frosting isn’t super stable and you might experience sliding or squishing with 3+ layers. Or try using a more stable frosting between the layers.


    Dutch-processed cocoa powder can not be substituted for unsweetened cocoa powder as they have different acidities, and that will affect the chemistry of the cake. (And the flavor is also much better)

    Black cocoa powder gives the cake and frosting a deep dark color. Only a little bit is needed. It can be replaced 1:1 with dutch-process cocoa powder, however your cake and frosting won’t be as dark. It also has an Oreo-like flavor that partially contributes to this cake.

    My recommendations:

    Droste Dutch-Processed Cocoa Powder or
    Rodelle Dutch-Processed Cocoa Powder
    The quality of your cocoa powder will determine the flavor of your cake.

    Wincrest Black Cococa Powder


    Cake recipe is adapted from King Arthur Flour

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