I make this cake whenever I have overripe bananas and a chocolate craving that won’t quit. It’s forgiving, quick to mix, and comes together in one bowl most of the time. The texture is dense and pudding-like, with pockets of melted chocolate and a gentle crunch from hazelnuts. It’s a weekday-worthy dessert that looks like you fussed for hours.

The flavor is balanced: ripe bananas bring natural sweetness and moisture, Dutch-process cocoa adds depth, and milk chocolate pieces give soft, creamy bites. A little buttermilk keeps the crumb tender without weighing it down. You get a cake that slices cleanly once it’s cooled, yet remains soft and comforting.

This recipe is practical. It uses pantry staples and a single small pan. I’ll walk you through each step, explain why ingredients matter, and offer troubleshooting tips for consistent results. Whether you’re baking for breakfast, a gathering, or just because, this one is worth keeping in rotation.

Ingredient List

2 large bananas — very ripe, mashed; they provide moisture, sweetness, and binding so you can skip extra sugar if bananas are very dark.
1 cup light brown sugar (1 cup minus 1 Tablespoon) — adds caramel notes and keeps the crumb soft; pack lightly if you prefer less sweetness.
1 teaspoon vanilla — rounds and lifts the banana and chocolate flavors.
1 egg — provides structure and helps the cake set while keeping it tender.
1/3 cup vegetable oil — keeps the cake moist and shelf-stable; neutral flavor so chocolate and banana shine.
1/3 cup buttermilk — adds acidity to react with baking soda, yielding a light, tender crumb.
1/2 cup Dutch-process cocoa powder — gives deep chocolate flavor and darker color; use exactly this if you want the intended taste.
1 cup all-purpose flour (1 cup minus 1 Tablespoon) — the base of the cake; measure carefully to avoid a dry or dense result.
1 teaspoon baking soda — the leavening agent with buttermilk; ensures rise and tender crumb.
1 pinch of salt — balances and enhances the chocolate and banana flavors.
2/3 cup milk chocolate pieces (from a good chocolate bar!) — chopped into pieces; they melt into soft pockets—use quality chocolate for best flavor.
1/3 cup chopped hazelnuts — adds crunch and a warm, toasty contrast to the soft cake; toast first for more flavor if you like.

Directions: Chocolate Banana Chocolate Chip Cake

Preheat the oven to 375°F (190°C). Line an 8-inch square pan with parchment paper, leaving an overhang on two opposite sides to lift the cake out after baking.
In a large bowl, mash the bananas until mostly smooth. Add the brown sugar, vanilla, egg, vegetable oil, buttermilk, and Dutch-process cocoa powder.
Whisk the banana mixture until smooth and uniform, scraping the bowl sides as needed.
In a separate bowl, whisk together the all-purpose flour, baking soda, and salt until evenly combined.
Add the dry ingredients to the wet mixture in two additions, gently folding with a spatula or whisk until just combined and the batter is thick (pudding-like). Do not overmix.
Fold the milk chocolate pieces and chopped hazelnuts into the batter until evenly distributed.
Pour the batter into the prepared pan and smooth the top with a spatula.
Bake on the middle oven rack for 35–45 minutes, or until a toothpick inserted into the center comes out without raw batter (melted chocolate on the toothpick is fine).
Cool the cake in the pan on a rack for about 15 minutes. Use the parchment overhang to lift the cake from the pan, transfer it to the rack, and cool until warm or room temperature before cutting and serving.

Why This Recipe Works

This cake balances moisture, structure, and flavor in simple ways. Ripe bananas supply both flavor and liquid; their natural sugars caramelize during baking and deepen the overall taste. Vegetable oil keeps the crumb tender and helps the cake stay soft for days. Buttermilk works with the baking soda to give lift without an over-aerated texture—what you get is a dense, pudding-like cake that still slices cleanly once cooled.

Using Dutch-process cocoa instead of natural cocoa shifts the chocolate to a rounder, less acidic profile. It complements the banana rather than competing with it. The milk chocolate pieces melt into sweet pockets—choose a chocolate you like to control how sweet or milky those bites will be. Hazelnuts add a necessary textural contrast; otherwise the cake can feel one-note.

The method minimizes handling: mash, whisk, fold. Folding in the dry ingredients in two additions prevents overstirring. That gentle technique preserves tenderness while ensuring everything is combined evenly.

Low-Carb/Keto Alternatives

Converting this cake exactly to a low-carb/keto version is challenging because bananas and brown sugar are high in carbs. If you need a lower-carb alternate, consider these ideas without treating them as a direct substitution for the original recipe:

Replace the all-purpose flour with a blend of almond flour and coconut flour—expect a denser, moister cake and reduce coconut flour to avoid a gummy crumb. Start with about 2 1/2 cups almond flour plus 1/4–1/3 cup coconut flour as a rough guide and test for texture.
Use a low-carb sweetener that measures like sugar (erythritol or allulose blends). Reduce total volume slightly because these sweeteners don’t behave exactly like brown sugar; adding a touch of molasses or a tiny amount of brown sugar substitute can mimic the caramel notes.
Replace bananas with unsweetened banana-flavored puree alternatives sparingly, or use mashed avocado for moistness and reduced carbs—the finished flavor will shift and won’t taste exactly like banana-chocolate cake.
Swap milk chocolate pieces for a sugar-free chocolate bar chopped into pieces; the texture and melt will differ slightly but gives similar pockets of chocolate.

These alternatives are starting points. Low-carb baking often needs trial and adjustment to match texture and sweetness preferences.

What’s in the Gear List

8-inch square baking pan — the recipe is sized for this pan to give the correct thickness and bake time.
Parchment paper — makes it easy to lift the cake from the pan and cut neat slices.
Mixing bowls — one large for wet ingredients, one for dry; you can use one large bowl if you prefer, but a separate bowl helps whisk flour evenly.
Spatula and whisk — a spatula for folding and a whisk for combining; both keep mixing gentle and even.
Measuring cups and spoons — accuracy matters, especially with flour and baking soda.
Toothpick or cake tester — to check doneness without cutting into the cake prematurely.
Cooling rack — helps the cake cool evenly and prevents a soggy bottom.

Steer Clear of These

Common mistakes are easy to avoid. Don’t overmix the batter after adding the flour. Overmixing develops gluten and gives a tough crumb. Fold until just combined and the batter looks thick and pudding-like.

A second pitfall is underripe bananas. If the bananas aren’t very ripe, the cake will lack sweetness and banana flavor. Let them get spotty or blackened for best results. Conversely, extremely liquid banana purée can throw off the texture—if your bananas are overly watery, drain a little liquid or reduce the buttermilk by a tablespoon or two.

Watch baking times. Every oven runs slightly differently. Start checking at 35 minutes; the toothpick should come out without raw batter. Melted chocolate on the tester is fine. If you pull the cake too early it will be gummy in the center; too late and it can dry out.

Make It Year-Round

This cake works in any season with small tweaks. In winter, swap hazelnuts for toasted pecans and add a pinch of cinnamon for warmth. In spring, fold in a handful of fresh or thawed raspberries with the chocolate for a bright contrast—toss berries lightly in flour first so they don’t sink.

For summer gatherings, serve slightly warm with a scoop of vanilla ice cream. In autumn, brush the cooled slices with a thin glaze made of melted chocolate and a splash of espresso or coffee liqueur to deepen the flavor.

The base is forgiving—seasonal toppings and accompaniments let you adapt it without changing the core mixing method or bake time.

Insider Tips

Quick checks and tweaks

To toast hazelnuts: spread on a sheet, bake at 350°F (175°C) for 8–10 minutes, then rub in a towel to remove skins. Cool before chopping.
If your batter seems too thin after folding in dry ingredients, chill it briefly (10–15 minutes). That helps it firm slightly and bake with less spread.
Use a good-quality milk chocolate bar for the pieces—you’ll taste the difference. Chop it into uneven pieces so some melt completely and others remain as chewy pockets.
Let the cake cool until at least warm before cutting. Cutting too hot will cause sticky slices and messy crumbs; too cold and the texture tightens.

Freezer-Friendly Notes

This cake freezes well, whole or in slices. Wrap airtight:

To freeze whole: cool completely, wrap tightly in plastic wrap, then foil. Freeze up to 3 months.
To freeze slices: wrap each slice in plastic then place in a freezer-safe bag. Press out air and freeze up to 3 months.
To thaw: transfer to the refrigerator overnight or unwrap and let sit at room temperature for 1–2 hours. Warm slices in a 300°F (150°C) oven for 8–10 minutes if you want them served warm.

Chocolate Banana Chocolate Chip Cake Q&A

Can I use natural cocoa instead of Dutch-process?

Yes, but natural cocoa is more acidic and has a brighter, sharper chocolate flavor. If you swap to natural cocoa, the flavor will change slightly. You may also notice subtle differences in color and how it interacts with buttermilk and baking soda.

What if I don’t have buttermilk?

Substitute by adding 1 tablespoon lemon juice or vinegar to 1/3 cup milk and let it sit 5 minutes. It’s not identical but provides similar acidity to react with baking soda.

Can I use a different nut or omit nuts?

Yes. If allergic or prefer a different profile, swap hazelnuts for walnuts, pecans, or almonds. Omitting nuts makes the cake softer; consider adding a tablespoon of seeds for texture if you skip them entirely.

How ripe should the bananas be?

Very ripe—dark spots or mostly black skin. They mash easily and are sweeter. If bananas are underripe, the cake will be less sweet and less flavorful.

Can I double the recipe?

Yes, double and bake in a larger pan (such as a 9×13) but check bake times; they will increase and you should test for doneness with a toothpick as directed.

Final Thoughts

This Chocolate Banana Chocolate Chip Cake is one of those recipes that feels both indulgent and approachable. It uses simple techniques and honest ingredients to deliver a reliably moist, chocolate-forward cake with delightful bursts of melted chocolate and nutty crunch. Keep ripe bananas on hand and a chocolate bar in the pantry—you’ll have a crowd-pleasing cake ready faster than you think.

Bake a slab for the week, freeze extras for later, and tweak toppings to match the season. Small adjustments—quality chocolate, toasted hazelnuts, or a warm serving with ice cream—make it feel special without adding stress. Enjoy the process and the taste.

Chocolate Banana Chocolate Chip Cake

A dense, chocolate-banana cake studded with milk chocolate pieces and chopped hazelnuts — made in an 8-inch square pan and baked until set.

Print Recipe Save it

Prep Time 15

Cook Time 40

Total Time 55

Servings 8 servings

Equipment

8-inch square pan
Parchment Paper
Oven
Mixing Bowls
Whisk
Spatula
rack

Ingredients

2 large bananasvery ripe bananas mashed
1 cuplight brown sugar 1 cup minus 1 Tablespoon
1 teaspoonvanilla
1 egg
1/3 cupvegetable oil
1/3 cupbuttermilk
1/2 cupdutch process cocoa powder
1 cupall-purpose flour 1 cup minus 1 Tablespoon
1 teaspoonbaking soda
1 pinch of salt
2/3 cupmilk chocolate pieces from a good chocolate bar!
1/3 cupchopped hazelnuts

Instructions

Preheat the oven to 375°F (190°C). Line an 8-inch square pan with parchment paper, leaving an overhang on two opposite sides to lift the cake out after baking.
In a large bowl, mash the bananas until mostly smooth. Add the brown sugar, vanilla, egg, vegetable oil, buttermilk, and Dutch-process cocoa powder.
Whisk the banana mixture until smooth and uniform, scraping the bowl sides as needed.
In a separate bowl, whisk together the all-purpose flour, baking soda, and salt until evenly combined.
Add the dry ingredients to the wet mixture in two additions, gently folding with a spatula or whisk until just combined and the batter is thick (pudding-like). Do not overmix.
Fold the milk chocolate pieces and chopped hazelnuts into the batter until evenly distributed.
Pour the batter into the prepared pan and smooth the top with a spatula.
Bake on the middle oven rack for 35–45 minutes, or until a toothpick inserted into the center comes out without raw batter (melted chocolate on the toothpick is fine).
Cool the cake in the pan on a rack for about 15 minutes. Use the parchment overhang to lift the cake from the pan, transfer it to the rack, and cool until warm or room temperature before cutting and serving.

Notes

Feel free to substitute the milk chocolate with dark or semisweet chocolate for a darker richer chocolate taste! I love using hazelnuts here because it’s really my favorite combo with chocolate, but any other nuts would work just as fine!
I love to make this Chocolate Banana Chocolate Chip cake in an8-inch square panand cut it further into squares like brownies, so they feel like a fluffier version of brownies.
I’ve also made this chocolate chip cake in a loaf pan or a muffin tin, even in a springform pan. All the same perfect texture, just different baking times.