Learn how to make this moist chocolate cake with swiss meringue buttercream! This cake tastes like it came from a bakery yet it is so easy to achieve at home. I walk you through each step and even break down the baking science a bit to understand what makes this cake so moist! 

A slice of Chocolate Cake With Swiss Meringue Buttercream

Happy Monday friends! I hope your weekend went well. I LOVE the weekend because I get two whole days at home spending time with Mr. BB and doing the “work” that I really want to be doing!

But then Monday arrives WAY too early. But on this Monday there is CAKE!!!!

I think Mondays feel doable when you have cake! Especially this crazy moist cake. I’m sorry if you are a person that can’t stand that word, but it is really the only way to describe this. It is out of the world, crazy moist!

When I made this recipe I really only cared about the cake as the vessel for my Swiss meringue buttercream. If you have been hanging around here the last couple of weeks, then you know I am in the middle of a series here at BB about meringue!

I made a Swiss Meringue for you on Wednesday and wanted to present to you a Swiss Meringue Buttercream today! BUT we also HAVE to talk about this cake and what makes it so moist!

Chocolate Cake With Swiss Meringue Buttercream with a slice taken out

I found this Moist Chocolate Cake recipe from Ina. Like I said, I didn’t plan on it being the focus of this post, but after I saw how amazing it turned out, I wanted to talk a little baking science about what makes this simple cake just so darn moist! Here is the formula below the way I adapted it for my use.

 Moist Chocolate Cake Formula
  • 1¾ cups (7.45 oz)  all purpose flour- 100%
  • ¾ cup (2.25 oz) unsweetened cocoa powder- 30%
  • 2 cups (14 oz) granulated white sugar- 188%
  • 1½ tsp baking soda
  • ¾ teaspoon salt
  • 2 large (3.6 oz) eggs- 48%
  • 1 cup (8 oz)  buttermilk- 107%
  • ½ cup (4 oz) oil- 53%
  • 1 tbsp vanilla extract
  • 1 cup (8 oz) hot coffee- 107%

If you aren’t familiar with using Baker’s Percentages, these numbers are probably looking a little weird to you. I wrote a post a while back going into depth about baker’s percentages, how to calculate them, and why they are useful.

But really the only thing you need to understand here is that the amount of flour is always set at 100% and then the percentage of every other ingredient is calculated off that based on the weight of the flour compared to the weight of the other ingredient.

When looking at these numbers for this cake I immediately notice that the sugar ratio is very high. We have discussed before about how sugar is hygroscopic, meaning it holds onto moisture. Because of this, high sugar cakes tend to be a more moist cake.

You will also notice that with the combination of the buttermilk and coffee we are looking at more than double the amount of liquid to flour by weight. For obvious reasons, this will also contribute to this cake being super moist!

You may also notice that this cake only calls for baking soda and not baking powder. Both buttermilk and coffee are acidic so these ingredients will get that baking soda activated and working to leaven the cake.

For this reason, it also does not matter in this particular cake like it does in other baked goods if you use natural cocoa powder or dutch processed. Either will work, but dutch processed will give a darker color and richer chocolate flavor to your cake.

This cake is actually super simple to put together. I’ll walk you through it.

Step 1- Place all of the dry ingredients into your mixing bowl. Mix all of the dry ingredients (flour, cocoa powder, sugar, baking soda, salt) together.

Dry ingredients mixed together

Step 2- Add in the wet ingredients, minus the hot coffee. Mix together the eggs, buttermilk, oil, and vanilla and mix into the dry ingredients just until incorporated. I quickly whisked all of the wet ingredients together in a large liquid measuring cup and then poured them in with the mixer on low. Scrape down the bowl.

Liquid ingredients added to dry ingredients

Step 3- Mix in the hot coffee. With the mixer still running, pour in the hot coffee. This is going to make your batter super liquidy and you are probably thinking that there is no way it is going to set. It will! Pinky promise. Also, if you don’t like coffee not to worry. This cake in no way tastes like coffee. The coffee just intensifies the chocolate flavor and also adds more moisture to the cake.

Hot coffee added to cake batter

Step 4- Pan and bake. Pour the batter evenly between two prepared cake pans. (I know, I know! I need to get some real cake pans and stop using disposable tins! I do have one set of real ones, but when I need two of the same size, I’m out of luck!) . Bake at 350F for 30-35 minutes.

Raw cake batter poured into 2 round cake pans

Step 5- Let them cool! Once those babies are done, let them cool for at least 20 minutes before depanning them.

Cake layers cooling on a wire rack

Now, moving on to that Chocolate Swiss Meringue Buttercream!

I gave you a detailed tutorial of how to make the Swiss Meringue last week, but I will quickly recap so we can get into the buttercream.

Swiss Meringue Buttercream

Swiss meringue buttercream is simply Swiss meringue that has butter beaten into it. It’s literally that simple. It is incredibly smooth and light, it pipes well, and is great for getting those super smooth cakes if you are good at that kinda thing, which I am not, so ignore that part.

If you need a more detailed tutorial on making Swiss Meringue, please see my Swiss Meringue 101 post! 

Step 1- Prep the butter. About 30 minutes before making your buttercream, remove the butter from the refrigerator and cut it into chunks, about 1 TBSP each. You want the butter to soften slightly, but you don’t want it to be warm.

Soft butter cut into squares

Step 2- Heat the Egg Whites and Sugar over a double boiler. Place your egg whites and sugar in a heat proof mixing bowl and set over a double boiler. Whisk and warm over the double boiler until the mixture reaches 160F. This mixture will be liquidy and smooth with all of the sugar melted.

Egg whites and sugar mixed together

Step 3- Whip the mixture. Whip the warm egg white/sugar mixture on high with the whisk attachment of your stand mixer until cooled and then continue until stiff peaks are reached.

Meringue at stiff peaks

Step 4- Beat the butter into the meringue. With the mixer on medium-high speed, add 1 chunk of butter a time. Let the piece incorporate into the meringue before adding the next one. At this point you mixture will most likely start looking curdled like cottage cheese. Don’t freak out! It will start going there, get worse, and then if you keep mixing it will smooth out and whip up!

Meringue after butter is mixed into it looking curdled

Curdled mixture is normal.

Step 4- Mix on high until you have a silky smooth frosting. At this point, you have regular swiss meringue buttercream. You can add in some vanilla or keep as is.

Swiss Meringue Buttercream looking silky smooth

But I added chocolate! 

Melted chocolate added to the Swiss Meringue Buttercream

And folded it in until I had this luscious chocolate swiss meringue buttercream!

Chocolate Swiss Meringue Buttercream

And I have to say, as a frosting hater, I liked this frosting! I was good with not having to push it off my cake. I liked it because it is not overly sweet and it has more of a real buttery flavor. It also stays super light and just isn’t heavy like a lot of frostings.

Then you just assemble you cake, frost, and serve! Don’t ask me for tips yet on frosting! I’m terrible at it but it is one of my goals I’m working on this year. Step 1, get a turn table! I like this video tutorial for how to smooth swiss meringue buttercream.

Moist Chocolate Cake With Swiss Meringue Buttercream

I hope you are enjoying this series on meringues. I would love to hear any requests from you for my next series. I have been talking about doing one an cooking eggs for a while now so maybe that should be next up!

I hope you Monday goes well! Just have some cake! It helps!

A slice of Chocolate Cake With Swiss Meringue Buttercream

One year ago: Sharp Cheddar and Thyme Cheese Puffs

Two years ago: Easy No-Knead Skillet Bread

Three years ago: Homemade Marshmallows and Sweet Ideas to Decorate for Valentine’s Day

A slice of Chocolate Cake With Swiss Meringue Buttercream
Yield: 10-12 Servings

Chocolate Cake with Swiss Meringue Buttercream

Prep Time 1 hour
Cook Time 35 minutes
Total Time 1 hour 35 minutes

This cake tastes like it came from a bakery yet it is so easy to achieve at home! Moist chocolate cake is layered with chocolate swiss meringue buttercream fit for any occasion! 


  • 1 3/4 cups (7.45 oz) all purpose flour
  • 3/4 cup (2.25 oz) unsweetened cocoa powder (natural or dutch processed- dutch processed will give the most chocolate flavor)
  • 2 cups (14 oz) granulated white sugar
  • 1 1/2 tsp baking soda
  • 3/4 tsp salt
  • 2 large (3.6 oz) eggs
  • 1 cup (8 oz) buttermilk
  • 1/2 cup (4 oz) vegetable or canola oil
  • 1 TBSP vanilla extract
  • 1 cup (8 oz) hot coffee
  • 6 large egg whites
  • 1 1/2 cups granulated sugar
  • 1 1/2 cups (3/4 pound) unsalted butter
  • large pinch of salt
  • 4 oz melted chocolate, cooled slightly


For the Cake
  1. Preheat your oven to 350F. Prepare two 9" cake pans by greasing well and flouring. Make sure the flour covers all of the pan and up the sides. Tap out the excess. Set aside.
  2. In the bowl of your stand mixer fit with the paddle attachment, or a large bowl with a hand mixer, mix together the flour, cocoa powder, sugar, baking soda, and salt.
  3. In a separate bowl or large liquid measuring cup, lightly whisk together the eggs, buttermilk, oil, and vanilla extract. With the mixer on medium speed, slowly pour the liquid ingredients into the dry ingredients. Mix just until incorporated. Scrape down the bowl.
  4. With the mixer still running, slowly pour in the hot coffee until just incorporated. The batter will be very thin and liquidy!
  5. Divide the batter between two cake pans and bake in a 350F oven for 30-35 minutes, until a cake tester comes out with just a bit of moist crumb stuck to it. Cool for at least 20 minutes before depanning!
  6. Run a butter knife around the edges of the pan. Place a cooling rack over the cake pan and holding with both hands flip the cake pan over. Gently tap the bottom to ensure the cake has released from the pan. This cake is very moist and fragile. Take extra care!
For the Buttercream
  1. About 30 minutes before making the frosting, take the butter out of the refrigerator and cut it into chunks. You want the butter to be slightly softened but still cool.
  2. Set up a double boiler (a pot filled with water not all the way to the top) and bring the water to a simmer.
  3. In a very clean heatproof bowl (I use the bowl of my stand mixer) whisk together the egg whites, salt, and the sugar.Set the bowl over the double boiler, making sure the water is not touching the bottom of the bowl, and whisk while the mixture heats to 160F. You can check with a kitchen thermometer, or if you do not have one the mixture will become very liquid as the sugar melts and it should feel very smooth between your fingers. This will take about 5-7 minutes.
  4. Transfer the mixture to your stand mixer (or you can do it with a hand mixer but it will take much longer), whip at high speed with your whisk attachment to cool the mixture down. Continue whipping at high speed until stiff peaks are reached. The mixture will become very thick, glossy, and almost marshmallow like. This will take about 6-8 minutes of whipping.
  5. Once stiff peaks are reached, switch to your paddle attachment and add in 1 piece of butter at a time while mixing on medium-high speed. Let the piece of butter incorporate in before adding in the next one.
  6. Once all of the butter is added, continue whipping until the mixture is smooth and fluffy. Your mixture will most likely start to look very curdled like cottage cheese before it gets very smooth. Don't worry, it will come together. Just keep whipping. If your butter was too warm and the mixture starts to look too thin, place the bowl in the refrigerator for about 20 minutes, then whip again.
  7. For Chocolate Swiss Meringue Buttercream- Swirl the slightly cooled melted chocolate over the buttercream and fold in.