I knew we had a winner after tasting the first bite of this luscious chocolate banana cake! With chocolate banana cake layers (using fresh bananas and a tasty chocolate cake mix), and my FAVORITE cocoa buttercream, I knew this cake would be nothing short of tasty perfection.

Keeping with the classics

I know, I know. This isn’t a cake with ten different kinds of textures and fillings and all the things. But without all those bells and whistles, does that make the cake basic or… a go-to classic? 😉

Using different crusts, textures, and fillings is something I’m no stranger to (I mean, there are SO many of my cakes with all those things). But this summer I’ve been trying to incorporate some simple classics that are more approachable for everyone. Sometimes you just need a freaking good chocolate banana cake, am I right?

That’s why we have this gorgeous classic before you today, my friends – your new go-to chocolate banana cake.

Have a few ripe bananas and a chocolate cake mix lying around? Good. You have this cake in your kitchen in less than 40 minutes start to finish.

How to doctor up a cake mix into a chocolate banana cake

For those who’ve been around here for more than two seconds, you know I specialize in making cake mixes taste DIVINE! Yes, divine. I wouldn’t say it if I didn’t mean it. haha

This means that, yes, you do use a cake mix, but you ADD things to it to make it taste like it’s from scratch, without the large margin for error, or all the extra work.

So you’ll need the following ingredients to add to your chocolate cake mix to make it taste just like it’s made from scratch!

  • Buttermilk
  • Eggs
  • Sour Cream
  • Ripe Bananas
  • Vanilla
  • Vegetable Oil
  • Mini Chocolate Chips

So for the doctored cake mix, you don’t use the water/eggs/oil quantities on the back of the package. Just follow the recipe below and you’ll be all set.

Which Cake Mix Should I Use?

I prefer Duncan Hines Dark Chocolate Fudge, but you can use whichever chocolate mix you can find. I know that cake mixes aren’t available everywhere, but if you can find 15.25oz or similar you should be all set. Just make sure to sift it when you add it into your batter for the silkiest texture.

THE BEST Cocoa Buttercream

You guys… this BUTTERCREAM is the BEST! I use this buttercream all the time. It’s my favorite! It pairs beautifully with my chocolate banana cake here.

It doesn’t go the chocolate-ganache method that I know we’ve used for dozens of my recipes. This one uses ALL cocoa. I figured most of you have cocoa in your pantry instead of high-end quality chocolate for your buttercream. So this recipe is probably already waiting in your pantry to be made right. this. moment. 🙂 Always a plus, right?

The main thing to remember for this cocoa powder-based buttercream is that it tends to get thick really fast. So I often find myself adding more heavy cream than I typically do to get the right texture. Don’t be afraid of the heavy cream on this one. That cocoa powder is like a sponge and soaks up the heavy cream much quicker than any other buttercream, for sure.

Speaking of cocoa powder…

THIS is a link to my favorite cocoa powder.

I mean, would you look at that gorgeous cake slice below?! It makes me want to eat another slice right now! Aaaaaand I’ve already had a couple after making this yesterday. Worth it.

Texture Cake Scraper

Using a textured cake scraper on the side of your cake is an easy way to make it extra special without having to pamper the smooth sides and edges. Here is a link to the set I used for this cake. It comes with a couple other textured options, which is always fun to play around with.

6″ or 8″ cake rounds?

I’ve included the instructions for both. But here’s the spoiler – they’re made exactly the same way. I typically do three 6″ cake rounds for my cakes, or two 8″ cake rounds. But for this one, I tried to do the three 8″ cake rounds. The only difference I noticed was they weren’t as tall as my 6″ or 8″ ones usually turn out. But with the buttercream layered between each layer, it still was a decent slice of cake and I would definitely be okay doing the three 8″ rounds again for this one.

Video tutorial

If you’d like to see the cocoa buttercream being made in a video, I added one to my Instagram page that can be of help to you :). But be warned, you may need a tall glass of milk after! Gotta love smooth chocolate buttercream.

I cannot wait to have you make my new chocolate banana cake! It’s divine and I’ve loved sharing the slices with friends and family. If you make the recipe, I’d love to see it! Make sure to tag me @bakingwithblondie or #bakingwithblondie on Instagram so I can join in on all the fun.

Happy baking!

xo,

Mandy

Get the Recipe: The Best Chocolate Banana Cake

5 from 1 vote
Soft Chocolate Banana Cake Layers with fresh bananas, and the most delicious cocoa buttercream and mini chocolate chips.
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Ingredients
 

Chocolate Banana Cake

  • 3/4 cup buttermilk , room temperature
  • 1/3 cup sour cream , room temperature
  • 3 whole large eggs , room temperature
  • 2-3 medium ripe bananas , the more brown the better
  • 1/3 cup vegetable oil
  • 1 Tablespoon vanilla
  • 1/2 cup mini chocolate chips , optional
  • 1 15.25oz Chocolate Cake Mix , I used the Dark Chocolate Duncan Hines for the best taste and texture

Cocoa Buttercream

  • 1 1/2 cup (or 3 sticks) unsalted butter , left out at room temperature for 10 minutes
  • pinch of salt
  • 1 Tablespoon pure vanilla
  • 1/2 + 1/2 cup heavy cream (plus 1/2 cup more after adding in the dry ingredients to thin out the buttercream
  • 1/2 cup quality cocoa powder
  • 7 cups powdered sugar

Extras

  • 1 cup mini chocolate chips

Equipment

  • inverted scallop cake scraper

Instructions
 

For the Banana Chocolate Cake

  • This recipe can be made into three 6" cake rounds, two 8" cake rounds (thick), or three 8" cake rounds (thin). The photos you see here are the three 8" cake rounds.
    Prep cake rounds with a swipe of shortening and a dust of flour.
  • Preheat oven to 325 degrees (convection bake). If doing traditional bake, you will just need to leave the cakes in for about 2-3 minutes longer.
  • In a large bowl, hand-whisk together all the ingredient except for the mini chocolate chips and cake mix. When thoroughly combined, stir in the chocolate chips, then sift in the cake mix. Gently stir it in, then split between the prepared cake pans. Bake for 20-25 minutes, or until the center of the cake is baked through.
  • Flip cake rounds out carefully onto a wire rack to finish cooling, wrap up in plastic wrap, then store in the freezer until you're ready to assemble the cake.

For the Cocoa Buttercream

  • In a stand mixer fitted with a paddle attachment, whip up the butter until it's light and fluffy. Scrape down the sides of the bowl.
  • Add in the pinch of salt, vanilla, 1/2 cup heavy cream, and cocoa powder. Mix up again to combine.
  • Slowly add in the powdered sugar, about 1/2 cup at a time. The buttercream will turn into an almost powder-like mixture, but don't worry! Add in your last 1/2 cup of heavy cream and it should thicken right up into buttercream.
  • Flip the mixture on high speed for 2 minutes, and add in a touch more heavy cream if needed to thin (your cocoa powder sometimes affects how thick or thin the buttercream will turn out for this one, I've noticed). If it's too thick, add in a touch more (2 Tablespoons-ish) of heavy cream. If it's too thin, add in 1/4 cup more of the powdered sugar. You're in charge of the consistency.

Assembly

  • On a cake turntable, and on a cardboard cake round, add on a dot of buttercream and carefully spread it out with an offset icing spatula. Place down the first cake layer.
  • Add on a layer of buttercream, then the next cake layer, and repeat. Crumb coat the cake and freeze for 3 minutes.
  • With a wooden spoon or spatula, hand-stir the buttercream to get out any air bubbles before adding on the final layer of buttercream to the cake. This will help it smooth out the buttercream much easier.
  • Spread on the rest of the buttercream onto the cake, use the cake turntable and offset icing spatula to create the swirl on top, and use a cake scraper (inverted scallop for this one) to create the decorative sides, leaving the top unfinished for a more rustic look.
  • Add on some mini chocolate chips on top around the outside rim of the cake. Enjoy!