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, just to make sure.
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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
- eggs—I bake with large eggs exclusively, which weigh 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
- 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!
- Diamond Crystal fine kosher salt
- chocolate—I've tested the frosting with both milk and dark chocolate and both work. The flavour will obviously differ
- icing sugar, also called powdered sugar or confectionner's sugar, not granulated sugar
- 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.
- 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
See recipe card for quantities.
Type of chocolate for frostings
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.
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!
Special equipment
I baked this banana cake in a square 9x9 pan so that I could cut it into square portions for a fun afternoon snack.
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.
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.
Combine the wet ingredients in a measuring cup or a bowl with a spout (banana, sour cream, and vanilla)
Use a small whisk to combine the wet ingredients until smooth.
Combine the softened butter and sugars in your mixing bowl using an electric hand mixer (or in the bowl of a stand mixer fitted with the paddle attachment).
Mix the butter and sugar for several minutes until fluffy and smooth.
Mix the eggs in one at a time, mixing for at least a minute until each egg completely disappears into the batter.
The batter should be smooth and fluffy at this stage.
Start by mixing in a third of the dry ingredients.
Mix in half the wet, then another third of the dry ingredients and the rest of the wet ingredients.
Use a spatula to scrape the bottom and sides of the bowl throughout the mixing process to ensure the ingredients are properly mixed.
Finish with the last of the dry ingredients. Do not overmix at this stage or the cake will be tough! You may want to switch to a spatula to finish mixing.
Pour the banana cake batter into a buttered square baking pan lined with parchment paper.
Use a mini offset spatula to evenly spread out and smooth the cake batter from edge to edge.
Bake the banana cake on the middle rack of a preheated oven.
The cake is done baking when the edges are golden brown and pull away from the sides and 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.
Unmould the cake onto a rack after it's cooled down for 10 minutes. This ensures the edges don't get damp from condensation.
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.
Storage
Store this cake covered in foil for up to one day at room temperature. For longer storage, refrigerate the cake. Let it stand at room temperature for 30 minutes to 1 hour before serving to let it warm up.
Top tip
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.
Serving suggestions
This cake is great served with homemade ice cream! This dark chocolate ice cream or cardamom ice cream would be great here!
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.
Other ways to use this chocolate frosting
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!
📖 Recipe
Coffee 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 bleached all-purpose 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 Cacao Barry Alunga 41% milk chocolate
- 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
Nutrition
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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!