Rich chocolate cake that’s not overly sweet. Black cocoa adds smoky, earthy notes to this wonderfully tender layer cake.
The darkest cake, ever.
A long, long time ago (ok, it was like two years but a lot has happened since) I made a chocolate cake with a chocolate mascarpone buttercream and used some black cocoa in it. I remember thinking the cake was lovely in person and I tried taking photos of it but felt they were just meh but the cake was gone and I had no other content one evening, so I posted it. It soared past anything I had done before then on IG (it continues to get a lot of attention on Pinterest) and it was all because of the color: it was black.
When I reposted it, I got a slew of messages asking for the cake recipe (not just the buttercream) which wasn’t mine. And it’s always bothered me that: a. The cake didn’t use black cocoa like the buttercream and b. The cake recipe wasn’t one of my own creations. It’s not like I don’t have a go-to chocolate cake recipe which I love even more than that one, I just hadn’t used it that particular day.
So it’s time to set this right with my own recipe for a cake that is 100% made with black cocoa. And because black cocoa is devoid of fat (more on that in a bit) full fat kefir/buttermilk ensures the cake is still ultra-tender, the way all cakes should be.
What is black cocoa and why make a black cocoa cake?
You are likely more familiar with black cocoa than you think; it’s the cocoa that’s used to make your favorite chocolate sandwich cookies: oreos! It’s a rare and special kind of cocoa because of the drama it adds to any baked good; turns it completely black. Truly,the color is wonderful but black cocoa is so much more than it’s color!
It’s earthy, smokey and tastes different than other cocoas. Because it’s ‘double dutched’ (alkalized) it’s got some almost bitter notes to it. When you use it in baking it really balances out the sweetness coming from the sugar (which in turn, is necessary for texture and structure and why I always ask you not to reduce it).
Kefir and buttermilk for Black Cocoa Cake
By now you know how much I love using buttermilk in my recipes, it makes the bake taste tangy and less one-dimensional but more than that it is responsible for a tender cake. Kefir, like buttermilk, is also a cultured milk, but where buttermilk is fermented with just lactic acid bacteria, kefir is fermented with several kefir grains (colonies of bacteria). They taste fairly similar and their consistency is similar as well.
While I’ve used it for years to make things like pancakes and waffles for the girl’s breakfast (it’s a great way to get them those healthy probiotics), I have begun using kefir frequently in place of buttermilk lately for a few reasons:
- I can find it in full fat more frequently, whereas I only find low fat buttermilk in my area.
- It lasts longer than buttermilk; a few months compared to a few weeks.
- It is tangier and creamier; so everything I love about buttermilk and more!
In this cake specifically I use full fat kefir because of the lack of fat from the black cocoa. The tangy taste also pairs nicely with the muted sweetness of black cocoa.
Ingredient info and substitutions for black cocoa cake
- Cake or all purpose flour: for a more tender and soft cake you can use cake flour, however it will be a little harder to frost (you can freeze it for a bit before you frost to make it easier).
- Black cocoa: If you cannot find it and still crave a rich chocolate cake, this can be turned into a dark chocolate cake simply by using dutch process cocoa.
- Kefir: the acidity of kefir balances the ph out in the cake and the fat compensates for the lack of fat in black cocoa. If you cannot find kefir, you can use full fat buttermilk or thinned out full fat greek yogurt. In a pinch you can use low-fat.
- Chocolate: I add melted chocolate to the buttercream to give it a richer chocolate taste but also to smooth it out. Since the cake itself is not very sweet I used a semi-sweet chocolate (55% cocoa solids) but you can use what you like.
Tips for frosting black cocoa cake
- Make the buttercream ahead of time and let it sit at room temperature
- The cooler the cakes are, the easier they will be to frost. I set mine in the freezer for about an hour before I frost.
- Buttercream temperature matters: if the buttercream is cold it won’t spread or pipe nicely, if it’s too warm it will make a mess. If you make it early, keep it refrigerated until an hour or two before you are going to use it.
Recipe for Black Cocoa Cake
Black Cocoa Cake
- two 8 or 9" round cake tins
Black Cocoa Cake Ingredients
- 1 cup unsalted butter at room temperature (226g)
- 2 cups granulated sugar 420g
- 1 tablespoon pure vanilla extract
- 1 teaspoon fine sea salt
- 4 large eggs
- 2 ½ cups cake flour 325g
- 1 cup black cocoa 85g
- 1 teaspoon baking soda
- 1 ½ cups full-fat kefir or buttermilk 350g
Black Cocoa Buttercream Ingredients
- 1 ½ cups unsalted butter at room temperature (3 sticks, or 330g)
- ⅓ cup black cocoa 28g
- 3 ½ cups organic powdered sugar sifted (455g)
- 1 tablespoon vanilla
- ½ tsp fine sea salt
- 113 g semi-sweet chocolate optional
How to make black cocoa buttercream
- Beat the butter with the vanilla and salt for 1 minute. Add the cocoa and powdered sugar and beat it until smooth. If adding the chocolate, heat it in the microwave until mostly melted then stir until smooth. Once it’s cool, stir it into the buttercream. If not using the chocolate, add milk or heavy cream until the buttercream is smooth (about 2-3 tablespoons). Set aside, in an airtight container or covered with plastic wrap.
How to make black cocoa cake
- Preheat the oven to 325. Grease and flour two tall 8” or 9″ round cake pans.
- Beat together the butter, sugar, vanilla and salt until light and fluffy, about 4-5 minutes.
- Add the eggs, one by one, allowing each to beat fully before adding another. Once all the eggs are in, beat for another 2 full minutes.
- Sift in the cocoa, baking soda and flour and with the mixer on, pour the kefir in and mix until the batter is fully incorporated (scrape the bottom a few times to make sure nothing got stuck and didn’t blend). Avoid overbeating this once the flour is in the batter or the cake will come out tough.
- Bake the cakes for 40-45 minutes, until a cake tester turns out clean or you can press the surface of the center of the cake and it springs back.
- Let the cakes cool in the pan for 5-10 minutes, then flip them onto a wire rack to fully cool. Transfer to the freezer, wrapped tightly in plastic wrap, for an hour or more.
- Frost the cakes when they are cold.