Learn how to make the best banana cake with chocolate frosting. The banana cake is moist and flavourful, made with very ripe bananas and sour cream. The frosting is a variation of a chocolate fudge frosting, made with milk chocolate, a little sour cream, and some espresso powder, reinforcing the chocolate flavour and adding a slight coffee taste to it.
I love the simplicity of single-layer cakes, especially a comforting banana snack cake like this. They bake in less time than a loaf cake, though the ingredient quantities are comparable, which means you get to eat your cake faster. And since my love for combining coffee and banana is real (remember I turned that combination years ago into a coffee banana smoothie, still one of my all-time fave smoothie flavours), well, here we go again: coffee and banana together in cake form with a milk chocolate fudge frosting.
I resisted the urge to add cardamom to the cake batter, but please, don't let that stop you. Cardamom would be so awesome in this recipe, as I have proven in this cardamom banana bread recipe. Perhaps I need to make this one again with cardamom, you know, to make sure.
Jump to:
This post is sponsored by Cacao Barry.
What You Need to Make This Cake
Like banana bread, banana cake has a simple list of ingredients. You'll also need to plan for the frosting (so more butter and sour cream than if you were to make the cake unfrosted).
- butter—preferably unsalted though salted will work in this recipe. You may adjust the salt in the cake batter if your salted butter has a lot of salt
- sugar—both granulated sugar and light brown sugar go in the cake, and icing sugar (also called powdered sugar or confectioner's sugar) in the frosting (sift the icing sugar for the smoothest frosting texture)
- eggs—I bake with large eggs, weighing approximately 56 grams (shell on) or 50 grams (shell off). Larger or smaller eggs may result in either a wetter cake or a dryer cake, respectively
- mashed banana—mash very ripe bananas that are quite soft and with a blackened peel. If the bananas are too young, they are more starchy, which will have an impact on the taste and texture of the cake
- sour cream—I bake with full-fat sour cream (14% fat). If you use lower fat sour cream, the texture of the cake may be dryer
- pure vanilla extract
- all-purpose flour—I bake with bleached all-purpose flour. You can try unbleached, but the texture and rise of the cake may differ
- chemical leaveners—you need both chemical leavening agents, baking powder and baking soda in this cake. If you aren't sure the difference, you can read about baking powder versus baking soda
- coffee:
- ground coffee beans, as in coffee grinds (the kind you would brew to make drip coffee)—these don't add too much flavour to the cake, but they do give the cake a lovely speckled look reminiscent of the banana seeds. Feel free to skip it if you want!
- instant espresso powder is a great way to add coffee to baked goods without adding water. Added to the frosting, it enhances the chocolate flavour but also add a subtle coffee taste that is so nice with chocolate and banana
- salt—use Diamond Crystal fine kosher salt, but if you only have regular table salt, add half the amount because it's saltier
- chocolate—I've tested the frosting with both milk and dark chocolate and both work. The flavour will obviously differ
- Dutch-processed cocoa powder—I bake with Cacao Barry extra brute cocoa powder, which is a dark cocoa powder with a little over 20 % fat.
See the recipe card for the exact ingredients and quantities.
Substitutions and Variations
- Chocolate—the frosting can be made with milk or dark chocolate but please use high-quality chocolate with a higher percentage of cocoa solids (at least 40 %) otherwise the frosting may lack flavour and be too sweet
- Nuts—you can add chopped nuts to the banana cake batter, for example chopped roasted peanuts or toasted walnuts would be excellent here
- Coffee—don't like coffee? Skip the coffee grinds and the espresso powder.
- Garnishes—I've topped this cake with candied pecans, chopped nuts, but also chocolate sprinkles. Use what you've got!
This coffee banana cake has the perfect texture, and it's not too sweet. It's just right for a thick slather of chocolate frosting made from the best chocolate for baking. I've tested the frosting with both 41 % milk chocolate and 70 % dark chocolate, and both work great.
For this recipe, I went with Cacao Barry Alunga milk chocolate (41 % cocoa) to make a slightly sweeter chocolate frosting but not too sweet! Alungo is referred to as milk chocolate for dark chocolate lovers because it has a balanced flavour. Trust me, Alunga is a great milk chocolate and makes excellent chocolate fudge frosting with sour cream, whether it's for a simple banana snacking cake like this banana cake like this or for a tall layer cake like this tall 6-inch vanilla cake with milk chocolate frosting.
You can order Alunga milk chocolate and most Cacao Barry products online via the Vanilla Food Company website and they ship across Canada and to the United States! In Quebec, you might find them at certain IGA grocery stores, as well as Aubut in Montreal.
How it's made
There are two components to this recipe: the banana cake and the chocolate sour cream frosting. Start with the banana cake and while the cake is cooling, you can make the frosting.
Step 1: Do your cake prep work first by buttering your cake pan (image 1), sifting your dry ingredients (image 2), and combining the wet ingredients together (image 3). Use a small whisk to combine the wet ingredients until smooth (image 4).
Step 2: Combine the butter and sugars in a bowl (image 5) and beat them together using an electric hand mixer (or in the bowl of a stand mixer fitted with the paddle attachment) until fluffy (image 6), then mix in the eggs one at a time (image 7).
Step 3: Once the batter is fluffy and smooth (image 8) add the wet ingredients (image 9) alternating with the dry ingredients (image 10), beginning and ending with dry ingredients. Use a spatula to scrape the sides and the bottom of the bowl to ensure all the ingredients are well mixed (image 11). Do not overmix at this stage or the cake will be tough!
Step 4: Pour the batter into the prepared 9x9 square cake pan and use a mini offset spatula to smooth it out (image 12). Bake until the edges are golden and begin to pull away from the sides (image 13). A cake tester inserted into the middle of the cake comes out clean.
You can also use a Thermapen to check the internal temperature of the cake. It should be around 93–95 °C when it's baked.
If you aren't experienced at making frosting, please refer to this post about how to make chocolate fudge frosting for more details and lots of step-by-step pictures.
Step 5: Make the chocolate frosting while the cake cools, melting the butter with the chocolate first (image 14), then after that mixture is smooth and has cooled down a little, you can sift in the cocoa powder, espresso powder, and icing sugar (image 16), also adding the sour cream. Beat the with an electric hand mixer (image 17).
Step 6: When the frosting is glossy, thick, and smooth (image 18), use a mini offset spatula to spread it on top of the cooled cake (image 19).
Serving Suggestions
You can garnish this cake with candied pecans/candied nuts, or nut/popcorn brittle. This cake is great served with homemade ice cream! Serve it with dark chocolate ice cream, cardamom ice cream, or even chocolate brownie ice cream!
Tip: I love this chocolate frosting and I make it all the time! I highly recommend making a half batch to garnish this marble loaf cake or a larger batch for this vanilla cake with milk chocolate frosting. It would also work great with this eggless chocolate cake!
Banana Cake Baking Tips
I baked this banana cake in a square 9x9 pan so that I could cut it into square portions for a fun afternoon snack.
Tip 1: Make sure that you take the time to prepare the cake pan before transferring the batter into the pan: I like to butter the pan and line the bottom with parchment. If the pan isn't non-stick, flour the sides too! This way, the cake can be unmoulded and frosted very easily.
Tip 2: Don't overmix the batter once you've incorporated the wet ingredients. If you do, the cake will be dense, tough, and possibly even gummy! You may incorporate the last of the dry ingredients by hand, with a spatula to avoid developing the gluten in the cake batter.
Tip 3: Unmould the cake onto a rack after it's cooled down for 10 minutes. This ensures the edges don't get damp from condensation and it will also speed up the time it takes for the cake to cool down.
Other Banana Recipes to Try
Want to bake more with bananas? Here are some other recipes to try, from an elaborate banana split cake to simple banana bread without baking soda.
If you tried this recipe for banana cake with chocolate frosting (or any other recipe on my website), please leave a ⭐ star rating and let me know how it went in the comments below. I love hearing from you!
📖 Recipe
Banana Cake with Chocolate Frosting
Ingredients
For the coffee banana cake
- 173 grams unsalted butter softened
- 100 grams granulated sugar
- 100 grams light brown sugar
- 2 large egg(s)
- 350 grams mashed banana from 3–4 large bananas
- 60 ml sour cream (14% fat)
- 10 mL pure vanilla extract
- 250 grams cake flour
- 23 mL ground coffee beans
- 10 mL baking powder
- 2.5 mL Diamond Crystal fine kosher salt
- 1.25 mL baking soda
For the milk chocolate frosting
- 58 grams unsalted butter
- 65 grams milk chocolate (41 % cocoa content)
- 140 grams icing sugar sifted
- 85 grams sour cream (14% fat)
- 23 grams Cacao Barry extra brute cocoa powder
- 5 mL instant espresso powder
- 5 mL pure vanilla extract
- 1.25 mL Diamond Crystal fine kosher salt
Decoration (optional)
- 30 grams candied nuts chopped, or toasted nuts chopped
Instructions
To make the coffee banana cake
- Preheat the oven to 350ºF (175 °C). Grease a 9x9-inch (23x23 cm) metal brownie pan (I used a Chicago Metallic pan you can find on Amazon). Line the bottom with parchment paper. Flour the sides of the pan if you find your cakes stick. Set aside.
- In the bowl of an electric mixer fitted with the paddle attachment or with an electric hand mixer, cream together the butter and the sugars. Scrape down the sides of bowls as needed.
- Add the eggs one at a time and beat them in. The mixture should be fluffy and well mixed
- Mash together the bananas with the sour cream and vanilla.
- In a separate bowl, whisk together the flour with the baking powder, baking soda, the coffee grounds, and the salt. You can also sift the dry ingredients if they are very lumpy, but note the salt and coffee grinds won't go through the sieve, so add them after sifting or transfer what is trapped to the bowl of dry ingredients.
- Alternate mixing into the cake batter the dry and wet, beginning and ending with dry ingredients. Mix until the batter ingredients are combined. Do not overmix!
- Transfer the batter to the prepared pan and smooth the surface with a mini offset spatula .
- Bake the cake for about 35 minutes until the edges are golden brown and a cake tester inserted in the centre comes out clean. Let cool 10 minutes then unmold onto a wire rack.
To make the milk chocolate frosting
- Melt together the butter with the Alunga chocolate on power level 5 of the microwave or over a double boiler. Set aside to cool slightly.
- Beat together the melted chocolate mixture with the rest of the ingredients into a smooth frosting
- Once the cake has completely cooled, smooth the frosting over top and decorate with candied or toasted nuts or even sprinkles.
Notes
- I baked this in a square 9x9-inch (23x23-cm) cake pan. Be sure to butter it and flour it, lining the bottom with square of parchment paper to make the cake easier to serve.
- Transfer the batter to the prepared pan and smooth the surface with a mini offset spatula.
- For the chocolate in the frosting, I've tested the recipe with both milk or dark chocolate and it works! Please use high-quality chocolate with a higher percentage of cocoa solids (at least 40 %). Otherwise, the frosting may lack flavour and be too sweet!
- Want to add nuts? You can add chopped nuts to the banana cake batter, for example chopped roasted peanuts or toasted walnuts would be excellent here
- Coffee—don't like coffee? Skip the coffee grinds and the espresso powder. The coffee grinds in the cake batter create a lovely flecked cake, reminscent of the banana seeds. The espresso powder in the frosting is discrete, but you can skip it altogether if you would prefer.
- Garnishes—I've topped this cake with candied pecans, chopped nuts, but also chocolate sprinkles. Use what you've got! Chopped popcorn brittle also makes a fun garnish.
Nutrition
This post is sponsored by Cacao Barry. I was compensated monetarily and with product. Thanks for supporting the companies that allow me to create content. As always, please know that I wouldn’t work with a sponsor nor recommend a product if it wasn’t worth it.
Laleh says
Hi Janice.
Thank you for sharing this recipe with us. I would like to try it but if I would like to replace the types of sugar that you have used by dark brown sugar, should I still use a total of one cup? Also, in that case, would I need to change the amount of butter or can it still stay the same? The reason is that I am trying to fix a similar recipe that was similar to this except that I wasn’t happy with it’s structure and it wasn’t sweet at all. Below is the recipe, I would appreciate it if you could help me fix it please.
Ingredients:
Butter 125
Dark brown sugar 120g
2 large eggs
Mashed bananas 270g
Self raising flour 240g
Baking soda 1 tsp
Sour cream 180
Milk 1 tblsp
Janice says
Hi, The proportions and ratios in your recipe are quite different than what I've been using, so it's hard for me to say how to fix it. It seems like you may have too much fruit+sour cream and not enough sugar, which could lead to structural issues or make the cake too wet.
To answer about your question about using dark brown sugar: yes, you can definitely replace both sugars with an equal amount of dark brown sugar, by weight! Your cake will likely be slightly darker inside, but I think that would taste veryy good! Hope that helps!
Natalie Dawn says
Do the bananas have to be over ripe or does freezing and thawing them make them mushy enough?
Janice says
Hi Natalie,
Better to use ripe bananas. Using frozen bananas is fine, but best to freeze riper bananas for the best texture in the end. I think "less ripe" bananas have more starch in them and this can have an impact on texture and flavour, even if they were previously frozen. Sometimes grocery stores sell overly ripe bananas for very cheap. Those would be perfect for this!
elodiesucree says
Waou!!! fabuleux quelle belle gourmandise!!! merci pour ce gourmand partage!! gros bisous et très bonne fin de semaine!
Janice says
Awww, merci beaucoup!