This chocolate banana marble bundt cake is what snack cake dreams are made of! It’s ultra moist and super easy to make. This chocolate banana cake is delicious on its own or with a simple dusting of powdered sugar but pour on an optional chocolate ganache glaze or pair it with a scoop of vanilla ice cream for a decadent dessert that’ll have everyone asking for seconds!

chocolate banana marble bundt cake with chocolate glaze

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This sweet treat has a simple sponge-cake base batter with added butter and sour cream to pack in the flavor and avoid a dry cake. Plus just a single extra step creates that beautiful swirl to give this chocolate banana bundt cake recipe the perfect balance of rich chocolate flavor and sweet banana goodness. It’s a delicious cake that doubles as the perfect recipe for casual weekday baking and for showing off at a potluck.

If you love banana recipes, don’t skip my classic banana pudding or this banana pudding cheesecake! They’re both a hit at every holiday and family gathering!

Key Ingredients

ingredients for chocolate banana marble bundt cake - all-purpose flour, ripe bananas, vanilla extract, sour cream, melted unsalted butter, dark brown sugar, eggs, regular unsweetened cocoa powder, optional chocolate chips

Ripe bananas. Choose ripe bananas that aren’t completely mushy. Bananas with scattered brown spots are perfect for baking. The brown spots indicate progress in the natural ripening process so the the bananas will have more natural sugar and natural banana flavor.

Regular unsweetened cocoa powder. My goal was to make this recipe as simple as possible so opting for cocoa powder over having to melt chocolate chips or bars was a no-brainer. In addition, Dutch-processed cocoa powder is a little hard to come by these days. However if dutch-processed is all you have feel free to sub it in for an equal amount in this recipe.

All-purpose flour. This bundt cake uses a sponge cake method and is based on the recipe for my red-velvet cheesecake tres leches. Since this chocolate banana uses a smaller amount of flour relative to many other cakes, all-purpose flour is the perfect option since it has enough gluten to support the structure of the cake.

Dark brown sugar. Complements the banana half of the cake batter with a caramel flavor. The acidity of the brown sugar also helps to tenderize the crumb of the bundt cake.

Eggs. Whole eggs are used and, unlike many sponge cake recipes that call for separating the yolks and the egg whites, they are whipped whole to keep this chocolate-banana swirl cake recipe simple!

Unsalted butter. Melted to incorporate more easily into the batter. Butter carries more flavor than vegetable oil does so it’s a great option since this cake doesn’t need to be refrigerated.

Full-fat sour cream. Packs more fat into the cake which translates into a moister cake with more flavor!

Milk chocolate chips. Used for an optional milk chocolate glaze topping.

Frequently Asked Questions

What kind of bananas are best for baking and desserts?

Most of the bananas found in a grocery store (unless other wise labeled) will likely be Cavendish bananas. Cavendish bananas are a type of dessert banana with a sweet & creamy flavor and smooth texture. These are what I use for this recipe and other banana desserts.

Burro and lady-finger bananas are typically less available but also fantastic options. These bananas have the same sweet and creamy flavor as Cavendish bananas but they tend to have additional tropical flavor notes like honey and apple! Burro and lady-finger bananas are considerably smaller than Cavendish so it is important to use the metric measurements for incorporating the banana puree instead of going simply off quantity. 1 Cavendish ≠ 1 Burro or 1 Lady-finger banana!

It’s worth noting that although plantains are technically type of banana, they are not what this recipe calls for.

slice of chocolate banana marble bundt cake

How do I pick the best bananas for baking?

When selecting bananas (or really any fruit) for baking or desserts the goal is to pick the fruit at peak ripeness. For bananas, this may be a little riper than a banana you pick for eating. Generally, bananas with a few brown spots that feel soft when moderate pressure is applied will give the best results. The skin of a good baking banana will also feel thinner compared to a green banana or a perfectly yellow banana.

Brown spots on bananas are an indication of the ripening process and at this point, most of the starch in the fruit has been converted to sugar. These bananas will also yield a more intense and natural banana flavor compared to ones that are less ripe or green.

In the same breath, be sure to choose or use bananas before they are completely brown or black. At this point, as the banana continues the ripening process the sugars start to convert to ethanol in a fermentation process. This causes the flavor of the bananas to change a bit and to some it can taste almost “spoiled.”

chocolate banana marble bundt cake on a cake stand

Why won’t my cake release from the bundt pan?

For easy release it’s important to properly prep your bundt pan. I use a baking spray like this one. It contains a mixture of fat and flour that functions as a barrier between the batter and your bundt pan to reduce the surface tension and prevent the cake from sticking to pan as it bakes. The more detail your bundt pan has, the more diligent you should be about spraying your pan since batter can easily get stuck in small corners. For example, a bundt pan like this one will need more baking spray than a standard bundt pan.

Tips for the Best Chocolate Banana Marble Bundt Cake

Use an oven thermometer. Ovens can have hotspots or run hotter or cooler than the displayed reading. Use a thermometer to take out the guess work. It also ensures that the bundt cake rises evenly and not too fast which would cause sinking. I use this one and hang it from one of the racks in my oven over my baking rack. Make sure you leave enough space for the cake to rise!

Use a kitchen scale & metric measurements! It is super important for the ingredients of this cake to be balanced. Too much flour and the cake will be dense. Too little and the cake sinks. Also, since brown sugar is not as fluid as granulated sugar, measuring by weight instead of volume is the best option. Weighing ingredients in grams or ounces is the best best for perfect, predictable and consistent results.
If you insist on using imperial measurements and using measuring cups make sure you spoon the flour into the measuring cups to avoid packing. After spooning the flour into the measuring cup level it using the straight edge of a knife.

Leave the oven door closed! Sponge cakes are sensitive to changes in temperature during baking. Opening the oven door in the middle of baking will let out all of hot air, drastically dropping the temperature in the oven and possibly causing the cake to sink. Don’t open the the door before the 25 minute mark to check on doneness.

How To Make the Chocolate Banana Marble Bundt Cake

Step 1. Preheat oven to 350°F.

Make the Base Cake Batter

Step 2. In a small bowl add all the dry ingredients except the cocoa powder (the all-purpose flour, baking soda, baking powder & salt). Mix to evenly incorporate.

all-purpose flour, salt, baking soda & baking powder mixed in a bowl

Step 3. Add the eggs, brown sugar & vanilla extract to the large bowl of a stand mixer with a whisk attachment. Whip on high speed for 3-5 minutes until the mixture is pale, fluffy and ribbons on itself.

Step 4. With the mixer still going at high speed add in the sour cream & melted butter. The eggs will deflate a bit. This is fine.

Step 5. Turn the mixer down the low speed and spoon in the flour mixture from earlier. Add about a ¼ cup at a time, waiting until the last addition has completely mixed in before adding another. Stop the mixer half-way through to scrape down the sides and ensure the flour mixture doesn’t collect along the sides of the bowl.
Avoid adding all of the flour mixture at once as this will deflate the whipped eggs.

Make the Chocolate and Banana Cake Batter

Step 6. Pour half of the batter in a separate bowl. Add the unsweetened cocoa powder to one half of the batter and the pureed bananas to the other half. Gently fold each add-in until completely incorporated.
Pureeing the bananas in a blender is the best way for a smooth batter. Avoid simply using mashed bananas as this can be chunky and result in an inconsistent texture in the final bundt cake.

base sponge cake batter split in two separate bowls

banana and chocolate cake batter in separate bowls

Step 7. Prepare a 10-cup bundt cake pan with baking spray. Dollop the cake batter around the prepared bundt pan, alternating between the banana cake batter and the chocolate cake batter. Repeat until all the batter has been used.
A 12-cup bundt pan can also be used but your final cake will be shorter.

Step 8. Using a skewer, swirl the batter being sure to get all the way to the bottom of the bundt pan so both the banana and chocolate cake batter are swirled throughout the cake.

marbled chocolate banana batter in a bundt cake pan

Step 9. Bake the chocolate banana marble bundt cake for 35-40 minutes or until the cake cake springs back when pressed gently.

Step 10. Allow the cake to cool in an upright position until the pan is comfortable to touch bare-handed. Once you can touch the pan, flip the bundt cake onto a wire rack or your desired serving plate while it is still a little warm. The cake should release easily. If it doesn’t, tap the the inverted pan and serving plate lightly on the counter to help jolt it out of the pan.
Once released, leave the pan in place on top of the cake to avoid the bundt cake drying out while it cools. With the cake released there should be enough room between the cake and the pan to avoid it sticking to the pan again.

Make the Optional Chocolate Glaze

Step 1. Add the water and milk chocolate chips to a microwave-safe bowl and microwave in 15-20 second increments, stirring until the chocolate is completely melted.
Alternatively you can melt the chocolate over a double boiler.

Step 2. Pour the warm chocolate glaze onto a cooled cake and store in an airtight container or cake dome until ready to serve. This cake does not have to be refrigerated.