This chocolate marble banana Bundt cake is inspired by my classic banana cake recipe. It’s a tried-and-true favorite among readers because the cake turns out perfectly moist, rich with butter, and packed with banana flavor. This version is baked in a Bundt pan and swirled with real chocolate ganache, so every slice has a decadent, fudge-like ripple. And don’t worry—you’ll have plenty of extra ganache left for drizzling on top!
One reader, Nancy, said: *“Yum! First time trying this, and I totally get why it has all 5-star reviews. Next time, I’ll throw in some nuts for a little crunch. ★★★★★”*
Another reader, Casey, shared: “This recipe is amazing. The cake is so moist, and the ganache takes it over the top. Can’t wait to bake it again! ★★★★★”
Chocolate Marble Banana Bundt Cake Details
Flavor: This cake starts with 1½ cups (345g) of mashed banana, so you know it’s loaded with real banana flavor. It’s also buttery with hints of cinnamon, brown sugar, and vanilla. And the best part? I’ll show you how to swirl in the ganache so that every single bite has a rich dark chocolate ribbon. If you love this combo, you’ll adore these banana chocolate chip streusel muffins too!
Texture: Bundt cakes are naturally denser than layer or sheet cakes because they’re so thick and heavy. This one is definitely substantial, but not as dense as pound cake—more like a super-moist, soft banana bread (as long as you don’t overbake it!).
Ease: The recipe has two main steps: making the cake batter and preparing the ganache. Both are simple, but timing is key. The ganache needs about 30 minutes to cool and thicken before swirling—otherwise, it’ll be too runny. My tip? Make the ganache first, so by the time your batter’s ready and the oven’s preheated, the ganache will be perfectly thick. You’ll use half inside the cake and save the rest for topping.
What makes this Bundt cake special is that instead of a basic chocolate swirl (like in marble loaf cake), it’s swirled with real chocolate ganache—not just chocolate-flavored batter. I wanted that fudge-ripple effect, like in ice cream, not just a mix of two cake batters. And if you warm up a slice in the microwave? The chocolate inside turns into gooey, melty magic—just like hot fudge sauce.
Swirled with Chocolate Ganache
Remember how to make ganache? If not, I’ve got a full chocolate ganache tutorial. All you need is two ingredients: real chocolate and heavy cream. I love using Baker’s or Ghirardelli semi-sweet baking bars (found near the chocolate chips).
After lots of testing, I learned that the ganache’s consistency (and how you swirl it) makes or breaks this cake. If it’s too thin and warm, it’ll blend into the batter, turning the whole cake into a chocolate-banana mix. If it’s too thick, it can create weird pockets of underbaked batter around it.
The fix? Let the ganache cool at room temp for about 30 minutes—until it’s as thick as gravy.
Perfecting the Banana Bundt Cake Batter
While the ganache cools, whip up the batter. I started with my banana cake recipe but tweaked it slightly—adding a bit more baking powder for lift and reducing the buttermilk. The original version turned out too wet with the ganache, but after adjusting, the texture was just right. (Want a plain banana Bundt cake? Just skip the ganache swirl!)
Layer the batter and ganache, then swirl them together generously.
Make Enough Ganache for the Topping
Every great cake needs a finishing touch, so let’s drizzle on even more ganache! The recipe makes enough to swirl inside and top the cake. You’ll need to reheat the reserved ganache to thin it for drizzling. Not in the mood for extra chocolate? Try topping it with salted caramel or the chocolate-peanut butter glaze from this chocolate chip loaf cake (readers rave about it!).