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This chocolate marble banana Bundt cake is based off of this banana cake recipe. It’s a reader favorite and loved recipe because the cake is always moist, buttery, and full of banana flavor. Here we’re baking it in a Bundt pan and swirling it with real chocolate ganache so each bite has a delicious fudge-like ripple. We’ll have extra chocolate ganache for the topping, too!

banana bundt cake topped with chocolate ganache

Chocolate Marble Banana Bundt Cake Details

  • Flavor: This chocolate marble banana Bundt cake starts with 1 and 1/2 cups of mashed banana, so you know there’s great flavor right from the get-go. It’s also buttery with notes of cinnamon, brown sugar, and vanilla too. And I’ll teach you how to swirl the ganache in such a way that literally every bite has dark chocolate as well! If you love these flavors together here, you’ll love them in these banana chocolate chip streusel muffins, too.
  • Texture: Because they’re so thick and essentially weigh themselves down, Bundt cakes are always denser than layer or sheet cakes. This is certainly a heavier cake, but it isn’t quite as dense as pound cake. It’s wonderfully moist and soft like banana bread, especially if you avoid over-baking.
  • Ease: The prep consists of two main components: making the cake batter and making the ganache. Both are very simple, but the success of the recipe depends on timing. The ganache used for the swirl must cool for about 30 minutes prior to using otherwise it’s too thin. I recommend making the ganache first because by the time you’re finished the cake batter and the oven’s preheated, the ganache will be ready. You’ll use half of the ganache inside the cake, then save the rest for the topping.
slice of chocolate marble banana bundt cake on plate

What you’ll love most about this chocolate marble banana Bundt cake is that unlike marble loaf cake, it’s swirled with real chocolate ganache and not chocolate flavored cake batter. I wanted the chocolate portion to be more like the chocolate swirl in fudge ripple ice cream and less like chocolate cake. Make sense? The best part is if you warm your slice back up in the microwave, the chocolate inside gets all melty like hot fudge sauce.

Swirled with Chocolate Ganache

Do you remember how to make chocolate ganache? I have an entire chocolate ganache tutorial page if you’re not sure. You need just 2 ingredients: real chocolate and heavy cream. I recommend Bakers or Ghirardelli brand baking semi-sweet chocolate bars, which is sold in the baking aisle near the chocolate chips.

***It took several test variations to learn that the consistency of the ganache (and how you swirl it) will make or break today’s cake recipe. If the ganache is too thin and warm, it will turn this into a thin chocolate banana cake batter. If it’s too thick, it will prevent the portions of cake batter surrounding it from baking so you’ll have this unpleasant and strange combination of baked and unbaked cake batter.***

How to avoid this: Let the ganache cool at room temperature for about 30 minutes until it’s about the consistency of gravy.

chopped chocolate and chocolate ganache

Perfecting the Banana Bundt Cake Batter

As the ganache cools and thickens, prep the cake batter. Banana cake was my starting point, but I add a little extra baking powder for some lift and slightly reduce the buttermilk. The original cake was strangely wet with the chocolate ganache, but after I reduced down the buttermilk, it cooked perfectly and had a lovely texture. If you’re looking for a plain banana Bundt cake, you can follow the recipe below and simply leave out the chocolate ganache swirl.

banana cake batter

Layer in the cake batter and ganache, then generously swirl together.

banana cake batter swirled with chocolate ganache
chocolate swirled banana bundt cake
banana bundt cake with chocolate ganache swirl

Make Enough Ganache for the Topping

Everything is complete with a little accessorizing, so let’s finish this Bundt off with even more ganache. The recipe below instructs you to make all of the ganache at once, then save half for the topping after the cake bakes and cools. You’ll have to reheat it so it’s thin enough to drizzle. Feel free to halve the ganache, then garnish the cake with salted caramel or use the chocolate peanut butter topping from this chocolate chip loaf cake instead. (Readers have loved that topping!)

Print
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slice of chocolate marble banana bundt cake on plate

Chocolate Marble Banana Bundt Cake

  • Author: Sally
  • Prep Time: 30 minutes
  • Cook Time: 65 minutes
  • Total Time: 6 hours (includes cooling)
  • Yield: serves 12 1x
  • Category: Cake
  • Method: Baking
  • Cuisine: American

Description

This is buttery moist banana Bundt cake swirled and topped with real chocolate ganache. Feel free to halve the ganache and only use it as the swirl. See step 1 below. For other garnish options, use salted caramel or the chocolate peanut butter topping from this chocolate chip loaf cake instead.


Ingredients

Scale

Ganache Swirl & Topping

  • two 4-ounce quality semi-sweet chocolate bars (113g each), finely chopped
  • 1 cup (8 ounces; 240ml) heavy cream or heavy whipping cream

Cake

  • 3 large ripe bananas (about 1 and 1/2 cups mashed)
  • 3 cups (375gall-purpose flour (spoon & leveled)
  • 1 and 1/2 teaspoons baking powder
  • 1 teaspoon baking soda
  • 1/2 teaspoon ground cinnamon
  • 1/2 teaspoon salt
  • 3/4 cup (170gunsalted butter, softened to room temperature
  • 1 cup (200ggranulated sugar
  • 1/2 cup (100g) packed light or dark brown sugar
  • 3 large eggs, at room temperature
  • 2 teaspoons pure vanilla extract
  • 1 and 1/3 cups (320ml) buttermilk, at room temperature*

Instructions

  1. Preliminary Note: This cake is swirled and topped with chocolate ganache. If you aren’t topping the cake with ganache, halve the ganache recipe so you’re only making what you need for the swirl. (Use one 4 ounce chocolate bar and 1/2 cup (120ml) heavy cream.)
  2. Make the ganache: Place chopped chocolate in a medium heat-proof bowl. Heat the cream in a small saucepan over medium heat until it begins to gently simmer. (Do not let it come to a rapid boil– that’s too hot!) Pour over chocolate, then let it sit for 2-3 minutes to gently soften the chocolate. Very slowly stir until completely combined and chocolate has melted. The finer you chopped the chocolate, the quicker it will melt with the cream. You should have about 1 and 1/2 cups of ganache. Set half aside (3/4 cup or 180ml) at room temperature uncovered until it has thickened into a gravy-like consistency, about 30 minutes. Use this in step 7. Cover and refrigerate the rest of the ganache to use as the topping in step 10. Ganache topping can be refrigerated for up to 5 days before using.
  3. Preheat the oven to 350°F (177°C) and generously grease a 10-inch Bundt pan. To guarantee the Bundt cake releases seamlessly, I strongly recommend using a heavy coating of nonstick spray. Our favorite pans include this one and this one.
  4. Make the cake: Mash the bananas until there’s hardly any lumps. I usually just use my mixer for this! Set mashed bananas aside.
  5. Whisk the flour, baking powder, baking soda, cinnamon, and salt together. Set aside.
  6. Using a handheld or stand mixer fitted with a paddle attachment, beat the butter on high speed until smooth and creamy, about 1 minute. Add both sugars and beat on high speed for 2 minutes until creamed together. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. Add the eggs and the vanilla. Beat on medium-high speed until combined, then beat in the mashed bananas. Mixture will be chunky and appear curdled– that’s ok. Scrape down the sides and up the bottom of the bowl as needed. With the mixer on low speed, add the dry ingredients in three additions alternating with the buttermilk and mixing each addition just until incorporated. Do not over-mix. The batter will be thick with some lumps. Makes about 6 cups of batter.
  7. You will use the slightly thickened ganache reserved for the swirl in this step. Pour about 1/3 of the cake batter (about 2 cups) evenly into prepared pan. Drizzle half of the ganache on top (about 6 Tablespoons). Swirl with a knife or toothpick. Evenly pour another 1/3 of the cake batter on top, followed by the rest of the ganache (about 6 Tablespoons), then the rest of the cake batter. Swirl everything together with a knife or toothpick. See photo above for a visual.
  8. Bake for 60-75 minutes or until a toothpick inserted into the cake comes out clean with just a couple lightly moist crumbs. This is a large, heavy cake so don’t be alarmed if it takes a little longer in your oven. If the cake is browning quickly in the oven, tent it with aluminum foil to help it bake more evenly.
  9. Once done, remove from the oven and allow to cool for 2 hours inside the pan. Then, invert the slightly cooled cake onto a wire rack or serving dish. Cool completely before topping, slicing, and serving.
  10. The ganache topping will be very thick by now. Warm it over low heat on the stove stirring constantly until thinned and drizzle-able consistency. Do not over-heat it. Or warm in 10 second increments in the microwave, stirring after each until thinned. Drizzle over cake, then slice and serve.
  11. Cover leftover cake tightly and store at room temperature for up to 2 days or in the refrigerator for up to 5 days. Cake tastes unbelievable warmed in the microwave for a few seconds and served with vanilla ice cream.

Notes

  1. Make Ahead Instructions: You can prepare the ganache used for the swirl and topping up to 5 days in advance. Make sure both are warmed/thinned out before using. The ganache used for the swirl should be a gravy-like consistency and the topping can be pretty thin. To warm/thin out, see step 10 above or step 5 in the chocolate ganache post. Cake with or without topping freezes well up to 3 months. Thaw overnight in the refrigerator, then bring to room temperature before serving.
  2. Chocolate: You can use high quality chocolate chips if needed (I prefer Ghirardelli semi-sweet chocolate chips), but I recommend using real chocolate baking bars. You can find them right next to the chocolate chips in the baking aisle. They are sold in 4 ounce bars. I like Bakers or Ghirardelli brands. You can use other varieties of chocolate too, such as milk chocolate (aka German Chocolate) or Dark Chocolate. Do not use white chocolate.
  3. Buttermilk: Buttermilk is required for this recipe. You can make your own DIY version of buttermilk if needed. Add 1 Tablespoon of white vinegar or lemon juice to a liquid measuring cup. Then add enough room temperature whole milk to the same measuring cup until it reaches 1 and 1/3 cups. (In a pinch, lower fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.

Keywords: chocolate marble banana bundt cake

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Reader Questions and Reviews

    1. Hi Skiey, heavy cream is essential to making the chocolate ganache swirl. You could skip the ganache swirls and bake our plain banana cake recipe in a bundt pan instead!

    2. Thank you so much! I ended up going to grab some Heavy cream, so excited to eat this bunt cake

  1. This cake was excellent! It was light, buttery, and everything you want a bundt to be. It was requested to become a part of the regular rotation at our Sunday Funday gathering. Thank you for the amazing recipe, Sally!

    1. Hi Michelle, this batter should work well for two loaf pans (or you can try halving the recipe for just one pan). We’re unsure of the exact bake time but use a toothpick to test for doneness.

    1. Absolutely! Cake with or without topping freezes well up to 3 months. Thaw overnight in the refrigerator, then bring to room temperature before serving.

  2. My 5 yo and I made this today for dessert. It was sooo good!! My only problem with it is that it’s not zero calories and I can’t stop eating it. Yum! Thank you for this recipe.

  3. The recipe calls for 1 and 1/3 cup buttermilk but in your instructions for making buttermilk, you mention 1 and 1/2 cups. Can you confirm which we should use? Thanks!

    1. Hi Julie, the recipe ingredients are correct– looks like the notes had a typo. Just fixed it. Thank you!

  4. My husband yelled at me because I have a ton of frozen bananas in the freezer. Usually I make banana bread but decided to try a cake instead. This came out beautiful, moist and delicious. I didn’t want to run to the store for heavy cream or buttermilk so I did make 2 substitutions that worked out fine. I used 8oz of chocolate ( only put the ganache in the cake) and 1/4 cup of 2% milk instead of the heavy cream. The ganache was perfect. Instead of butter milk I used 1 and 1/4 cup of sour cream thinned with a quarter cup of the 2% milk. I can’t imagine it could have been any better but maybe richer with the cream and buttermilk? Anyway it was a win win for my family. Thank you for sharing the recipe!

  5. I use grams and ml. when baking. Do you use King Arthur flour?. King Arthur is heavier than other flours.

    1. Shouldn’t be problem if you follow the directions on the package to sub for buttermilk!

  6. Hello, can I make a normal chocolate bundt cake by opting out the banana?

    1. Hi Fan, We recommend using the base batter for this chai spice cinnamon swirl Bundt cake. Just leave out the spice swirl and add the ganache swirl. Let us know how it turns out!

  7. Delicious and moist, It was perfect with extra chocolate ganache on top!

  8. How can I make this cake without bananas? I would love everything else and would love to make a bundt marble cake w ganache? What do you recommend? Thank you. I LOVE your recipes.

    1. Can I butter Bundt pan instead of spraying with Pam?
      Also, if I butter Bundt pan, should I flour pan too?

      1. Hi Linda, we really find Pam to be the absolute best way to grease a bundt pan for a seamless release. If you use butter make sure to grease it very generously.

  9. I always have complete faith in your recipes, they’ve never let me down, and this one was no different. The chocolate swirl was delicious and looked so fancy running through the cake. Birthday boy was very pleased! The cake itself was really moist and had a great texture. I actually followed this recipe exactly (which is very unusual for me) but I’m really looking forward to trying it again with maybe some added spices or possibly a bit of whiskey or something to the ganache.

  10. last time i made this i after prepping the bundt paper with shortening i dusted it with cocoa powder rather than flour. really kicked it up a notch.

  11. Also, can I add a teaspoon of espresso instant coffee to the ganache before melting chocolate & cream?

    1. Can’t see why not! We recommend adding it to the chocolate before pouring over the warm heavy cream.

    2. Can I use butter then a coating of flour to prepare Bundt pan instead of spraying with Pam?

      1. Hi Linda, we really find Pam to be the absolute best way to grease a bundt pan for a seamless release. If you find butter & flour works best for you, you can certainly use that method!

  12. This cake was outstanding and the recipe very clear and easy to follow.

  13. My Bundt pan is 9.5×3.4 inches. It’s a Wilton Bundt pan.

    Is this pan too small for the chocolate marble banana cake recipe?

    1. Hi Linda, your pan may be a smidge too small, but feel free to fill it as you see in the photos (not all the way to the top) and either discard or use any leftover batter for a few cupcakes/muffins on the side. Bake time may be different as well. Let us know what you try!

  14. Just finished making chocolate marble banana cake. It’s in the oven right now.

    From the video it looks like you added ganache 3x instead of 2 as the recipe states.

    Do you add some ganache with final layer of batter?

  15. This cake was amazing! It was another huge hit at work. I will definitely bookmark this recipe. I made this cake twice in a month, is that good!

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