The Ultimate Moist Banana Sponge Cake with Rich Dark Chocolate Buttercream
Prepare to fall in love with the most incredibly soft and delightfully spongy banana sponge cake, perfectly complemented by a luscious, velvety dark chocolate buttercream. This isn’t just a cake; it’s a celebration of two classic flavors that were simply made for each other: sweet, ripe bananas and deep, intense dark chocolate. This simple yet sophisticated layer cake is surprisingly easy to bake, promising a truly delicious treat for any occasion.
If you’re a devoted fan of banana cake, then this recipe is an absolute dream come true. Imagine sinking your teeth into a slice of pure comfort – a cake so moist and tender it practically melts in your mouth, each bite bursting with the natural sweetness of ripe bananas. Topping this exquisite base is a homemade, simple-to-make chocolate buttercream, crafted with rich dark chocolate, adding an irresistible layer of indulgence. It’s an effortlessly elegant dessert that tastes like it came from a professional bakery, yet is easily achievable in your own kitchen.
Looking for more delightful baking projects? Explore our other sensational layer cake recipes and decadent treats like Espresso Brownies, Small Batch Brownies, and the irresistible Peanut Butter Brookies.
WHY THIS HOMEMADE BANANA CAKE RECIPE IS A MUST-TRY
There are countless reasons why this particular banana sponge cake recipe stands out, promising a delightful baking experience and an even more delightful eating experience. Here’s why this recipe truly works wonders:
- Unbelievably Moist Banana Cake: This isn’t just any banana cake; it’s a truly soft, incredibly moist, and wonderfully flavorful creation. The secret lies in using perfectly ripe bananas, which lend natural sweetness and an unparalleled tenderness to the sponge. Every forkful is a testament to its irresistible texture and rich banana flavor.
- Decadent Dark Chocolate Buttercream: Complementing the light banana sponge is a super smooth, intensely chocolatey buttercream. Made with quality dark chocolate, it offers a rich, deep flavor without being overly sweet, providing the perfect counterpoint to the banana. It’s remarkably easy to whip up, even for beginner bakers, yet tastes incredibly luxurious.
- Effortless Elegance: This cake proves that stunning desserts don’t require complicated decoration techniques. Simply spreading the luscious buttercream over the banana sponge creates a rustic yet elegant finish. It’s a no-fuss kind of cake that looks beautiful on any table, making it perfect for both casual family treats and more formal gatherings.
- Classic Flavor Combination: The pairing of banana and dark chocolate is a timeless classic that never disappoints. The natural sweetness of the bananas beautifully balances the slight bitterness and richness of the dark chocolate, creating a harmonious flavor profile that will leave everyone craving another slice.
KEY INGREDIENT NOTES FOR THE BEST BANANA SPONGE CAKE
Achieving a perfect banana sponge cake starts with understanding the role of each ingredient. Below are some key notes to ensure your cake turns out exceptionally moist and flavorful. For a complete list of ingredients and precise measurements, please refer to the detailed recipe card at the bottom of this post.
- Very Ripe Bananas: The star of the show! You’ll need 1-2 large, very ripe bananas (about 180g). The riper the bananas (those with plenty of brown spots), the sweeter and more flavorful they will be, imparting a natural moistness and intense banana flavor to your cake. Don’t underestimate the power of brown spots!
- Unsalted Butter (Room Temperature): For both the cake layers and the buttercream, it’s crucial that your butter is at proper room temperature. This means it should be soft enough to indent with your finger but not melted. Room temperature butter creams beautifully with sugar, incorporating air that creates a light and airy texture in your cake and a smooth, fluffy buttercream.
- Large Eggs (Room Temperature): Just like butter, eggs at room temperature are essential. They emulsify more effectively with other ingredients, creating a smoother, more uniform batter. This leads to a better rise and a more consistent, tender crumb in your finished banana cake. Take them out of the fridge at least 30 minutes before baking.
- Full-Fat Milk (Room Temperature): Opt for full-fat milk as it contributes significantly to a softer, more tender, and richer cake. The higher fat content adds moisture and richness, resulting in a wonderfully delicate crumb. Again, ensure the milk is at room temperature to prevent it from seizing the butter mixture.
- Dark Chocolate (for Buttercream): For the most luxurious chocolate buttercream, use a good quality semi-sweet or dark chocolate (around 50-70% cocoa solids). This provides a rich, deep chocolate flavor that perfectly complements the banana without being overly sweet.
- All-Purpose Flour, Baking Soda, Baking Powder, and Salt: These dry ingredients are carefully balanced to give your sponge cake its perfect rise and tender structure. Sifting them together ensures even distribution and prevents lumps, contributing to a consistently beautiful crumb.
STEP-BY-STEP INSTRUCTIONS – BAKING THE MOIST BANANA CAKE LAYERS
Creating this incredibly moist banana sponge cake is a straightforward process, even for those new to baking. To achieve the best results, you’ll need either a stand mixer fitted with a paddle attachment or a reliable electric hand mixer. We’ll be using a 20×20 cm (8×8 inch) baking pan, meticulously lined with baking paper for easy release. Remember, the full, detailed recipe is provided in the recipe card below.
Preparation is Key: Before you begin mixing, ensure your oven is preheated to 170ºC (340ºF) for conventional baking. Also, prepare your 20×20 cm (8×8 inch) baking pan by greasing it and lining the bottom with parchment paper. This critical step ensures your cake doesn’t stick and comes out perfectly.
STEP 1: Combine Dry Ingredients. In a medium-sized bowl, sift together the all-purpose flour, baking soda, baking powder, and salt. Sifting helps to aerate the flour and ensures all leavening agents are evenly distributed, leading to a light and consistent cake crumb. Set this mixture aside.
STEP 2: Prepare Bananas and Milk Mixture. Mash your very ripe bananas thoroughly in a separate bowl until smooth; chunky bits are fine if you prefer a more rustic texture. In another small bowl, whisk together the full-fat milk and vanilla extract. Keep both of these prepared mixtures on standby.
STEP 3: Cream Butter and Sugar. In the bowl of your stand mixer (or a large bowl with a hand mixer), add the room temperature butter and granulated sugar. Whisk these together on high speed for 2-3 minutes. This step is vital as it incorporates air into the mixture, which will make your cake light and airy. Continue mixing until the mixture becomes visibly light in color and fluffy in texture.
STEP 4: Incorporate Eggs. Reduce your mixer speed to low. Add the eggs one at a time, ensuring each egg is fully incorporated into the batter before adding the next. This gradual addition helps to maintain the emulsion and prevents the batter from curdling, leading to a smoother, more stable mixture.
STEP 5: Alternate Wet and Dry Ingredients. With the mixer still on low speed, begin adding the dry ingredients alternately with the milk mixture. Start by adding approximately one-third of the sifted flour mixture and mix until just combined. Next, gently fold in the mashed bananas. Follow this with another one-third of the flour mixture, then the milk and vanilla mixture. Finally, add the last one-third of the flour mixture. Mix until just combined – be very careful not to overmix the batter, as this can develop the gluten too much, resulting in a tough, dense cake.
STEP 6: Final Gentle Mix. Remove the bowl from the mixer. Use a rubber spatula to give the batter a final gentle fold. This ensures that all ingredients, especially any at the bottom of the bowl, are fully incorporated without overworking the batter.
STEP 7: Bake to Perfection. Pour the prepared cake batter evenly into your lined baking tin. Transfer the tin to your preheated oven and bake for 28-30 minutes. The cake is done when a wooden skewer or cake tester inserted into the center comes out clean, with no wet batter attached. The top should also be golden brown and spring back lightly when touched.
STEP 8: Cool Completely. Once baked, remove the cake from the oven and allow it to cool in the baking pan on a wire rack for 5-10 minutes. This resting period helps the cake to firm up. After this time, gently invert the cake onto the cooling rack, remove the baking paper, and let it cool down completely before frosting. A fully cooled cake prevents the buttercream from melting.
STEP-BY-STEP INSTRUCTIONS – CRAFTING THE CHOCOLATE BUTTERCREAM AND ASSEMBLING YOUR CAKE
Once your banana cake has cooled completely, it’s time to prepare the rich dark chocolate buttercream and bring your masterpiece together. This buttercream is incredibly simple and delivers a truly indulgent finish.
STEP 1: Melt Dark Chocolate and Heavy Cream. In a heatproof bowl, combine the dark chocolate and heavy cream. Gently melt them together either over a bain-marie (a pot of simmering water) or in the microwave in short bursts, stirring frequently, until smooth and fully combined. It’s crucial that this chocolate mixture cools down to room temperature before you add it to the butter, otherwise, it will melt your carefully creamed butter and result in a greasy, runny buttercream.
STEP 2: Sift Powdered Sugar. While the chocolate cools, sift the powdered sugar into a bowl. Sifting removes any lumps, ensuring your buttercream is silky smooth. Set aside.
STEP 3: Cream the Butter. In the bowl of your stand mixer (or a large bowl with a hand mixer), cream the room temperature butter on medium-high speed for about 4 minutes. You want the butter to become visibly lighter in color and incredibly fluffy. This aeration is key to a light and airy buttercream.
STEP 4: Add Vanilla and Powdered Sugar. Scrape down the sides of the bowl to ensure all butter is incorporated. Add the vanilla extract and the sifted powdered sugar to the creamed butter. Start mixing on low speed until the sugar is just incorporated to prevent a cloud of sugar dust. Once combined, increase the speed to low-medium and mix for another 2 minutes, scraping down the sides as needed. This ensures a smooth, lump-free base.
STEP 5: Incorporate Cooled Chocolate. Finally, add the completely cooled dark chocolate mixture to the butter and sugar. Mix on low speed until everything is fully incorporated and the buttercream is uniformly chocolatey and smooth. Scrape down the sides of the bowl one last time and give it another quick mix to ensure no streaks remain.
Buttercream Tip: If your buttercream feels too soft or runny at any point, especially if your kitchen is warm, place the bowl in the refrigerator for 5-10 minutes. Afterwards, give it a good re-mix with your stand or hand mixer until it reaches the desired consistency before frosting your cake. This will help it firm up without separating.
STEP 6: Assemble Your Banana Cake. Take your completely cooled banana sponge cake. Using an offset spatula or a knife, spread the luxurious chocolate buttercream evenly over the top of the cake. You can create smooth, clean edges for a polished look or leave it with beautiful swirls for a rustic, homemade charm. Serve immediately and enjoy!
EXPERT BAKING TIPS FOR A PERFECT MOIST BANANA CAKE
Achieving baking perfection often comes down to a few key techniques and considerations. Here are some expert tips to help ensure your banana sponge cake with dark chocolate buttercream turns out flawlessly every single time:
- Always Use a Kitchen Scale: For unparalleled accuracy in baking, a kitchen scale is your best friend. My recipes, and indeed most professional baking recipes, default to grams because it is the most precise way to measure ingredients. Unlike volume measurements (cups), weighing ensures consistent results, preventing discrepancies that can arise from how ingredients are scooped or packed. This precision is especially important for delicate sponges like this banana cake.
- Do Not Overmix Your Batter: Once you’ve added the flour mixture, mix only until the ingredients are just combined. Overmixing develops the gluten in the flour, which can lead to a tough, dry, and chewy cake rather than a tender, soft sponge. After using your mixer, a gentle final fold with a rubber spatula is highly recommended. This ensures all ingredients from the bottom and sides of the bowl are fully incorporated without overworking the batter, contributing to a consistently tender crumb.
- The Impact of Light vs. Dark Baking Pans: The type of baking pan you use significantly affects the final texture and color of your cake. For the absolute best results, I highly recommend using an aluminum baking pan. These pans are lighter in color and therefore reflect heat rather than absorbing it. This allows the cake to bake more gently and evenly, resulting in a softer, lighter-colored crust and a consistently moist interior. Conversely, dark-colored baking pans absorb more heat, leading to a darker, sometimes drier crust, which can negatively impact the overall moisture of the cake. Always ensure your pan is greased and lined with baking paper, regardless of its color.
- The Importance of Room Temperature Ingredients: As mentioned in the ingredient notes, room temperature butter, eggs, and milk are non-negotiable for the best cake. They emulsify more easily, creating a smooth, homogenous batter that traps air efficiently, resulting in a lighter texture and better rise. Cold ingredients can cause the batter to curdle, affecting the cake’s consistency.
- Don’t Rush the Cooling Process: It can be tempting to frost a cake that’s still warm, but resist the urge! A warm cake will melt your beautiful buttercream, causing it to slide off and make a mess. Ensure your cake layers are completely cool to the touch before you even think about applying the frosting. Patience here will be rewarded with a perfectly presented cake.
FREQUENTLY ASKED QUESTIONS ABOUT BANANA SPONGE CAKE
Absolutely! This recipe can easily be doubled to create a stunning two-layer cake. If you choose to do so, I recommend using two 20 cm (8 inch) or 22 cm (9 inch) round baking tins. Adjust the baking time slightly as needed, and bake until a cake tester inserted into the center of each layer comes out clean.
Yes, you certainly can! While the recipe is written for a square 20×20 cm pan, you can easily substitute it with an 20 cm (8 inch) or 22 cm (9 inch) round baking pan. The baking time should remain similar, but always rely on the cake tester method to confirm doneness.
The best way to determine if your cake is done is by using a cake tester or a thin wooden skewer. Once the recommended baking time has passed, gently insert the tester into the very center of the cake. If it comes out clean with no wet batter or moist crumbs attached, your cake is ready! If it’s still wet, bake for a few more minutes and test again.
Very ripe bananas are key for maximum flavor and moisture. If your bananas aren’t quite ripe enough, you can speed up the process by baking them in their peels on a baking sheet at 150°C (300°F) for 15-30 minutes, or until the peels turn completely black. Let them cool, then scoop out the soft flesh.
Absolutely! This banana sponge cake is wonderfully versatile. Feel free to fold in about ½ cup of chopped walnuts, pecans, or even chocolate chips into the batter at the very end of Step 5 for added texture and flavor. Just be mindful not to overmix.
STORAGE INSTRUCTIONS FOR YOUR BANANA SPONGE CAKE
To keep your delicious banana sponge cake with chocolate buttercream fresh and moist, proper storage is essential. Here’s how to best store and enjoy your baked creation:
Once the cake has completely cooled and been frosted, store it in an airtight container or under a cake dome in the refrigerator. This will prevent it from drying out and will keep the buttercream firm. When you’re ready to enjoy a slice, take the cake out of the fridge approximately 30-60 minutes before serving, allowing it to come closer to room temperature. This will ensure the cake sponge is at its softest and the buttercream is wonderfully creamy. For the very best taste and texture, aim to enjoy your banana sponge cake within 2-3 days of baking.
While the cake can be frozen (see FAQ for more details), it truly shines when enjoyed fresh. Always keep it covered to maintain its irresistible moisture and prevent it from absorbing any fridge odors.
Other Easy Cake Recipes To Try
If you loved baking this banana sponge cake, you’ll definitely want to explore these other fantastic and easy cake recipes from our collection:
- Best Pumpkin Bread with Streusel Topping and Pumpkin Spice Glaze
- 25 Best Summer Dessert Ideas
- 20 Best Easter Dessert Ideas
- Lemon Poppy Seed Cake
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Banana Sponge Cake with Dark Chocolate Buttercream
Pin Recipe
Ingredients
BANANA CAKE LAYERS
- 180 g very ripe bananas
- 175 g all-purpose flour
- ½ teaspoon baking powder
- ¾ teaspoon baking soda
- ½ teaspoon salt
- 75 g full-fat milk
- ½ teaspoon vanilla extract
- 60 g butter room temperature
- 125 g granulated sugar
- 2 large eggs room temperature
CHOCOLATE BUTTERCREAM
- 50 g semi-sweet dark chocolate
- 40 g heavy cream
- 50 g butter room temperature
- 90 g powdered sugar
- ½ teaspoon vanilla extract
Instructions
BANANA SPONGE CAKE LAYERS
- Preheat your oven to 170ºC (340ºF) for conventional baking. Prepare a 20×20 cm (8×8 inch) baking pan by greasing and lining the bottom with parchment paper.
- In a medium bowl, sift together the all-purpose flour, baking powder, baking soda, and salt. Set aside.175 g all-purpose flour, ½ teaspoon baking powder, ¾ teaspoon baking soda, ½ teaspoon salt
- Mash the very ripe bananas until smooth and set aside. In a separate small bowl, mix together the full-fat milk and vanilla extract; set aside.180 g very ripe bananas, 75 g full-fat milk, ½ teaspoon vanilla extract
- In the bowl of a stand mixer fitted with a paddle attachment (or using a hand mixer), combine the room temperature butter and granulated sugar. Whisk on high speed for 2-3 minutes until the mixture is light, pale, and airy.125 g granulated sugar, 60 g butter
- Reduce the mixer speed to low. Add the room temperature eggs one at a time, ensuring each egg is fully incorporated into the batter before adding the next. Scrape down the sides of the bowl as needed.2 large eggs
- Continue on low speed. Add ⅓ of the sifted flour mixture and mix until just combined. Then, add the mashed banana and mix until incorporated. Add another ⅓ of the flour mixture, mix. Then add the milk/vanilla mixture, mix. Finally, add the last ⅓ of the flour mixture and mix until just combined. Be careful not to overmix the batter.
- Using a rubber spatula, give the batter a final gentle fold by hand to ensure everything from the bottom and sides of the bowl is thoroughly combined.
- Pour the cake batter into the prepared baking tin and spread evenly. Bake for 28-30 minutes, or until a cake tester inserted into the center comes out clean.
- Let the cake cool in its tin on a wire rack for 5-10 minutes. Then, gently remove the cake from the tin and transfer it directly to the cooling rack to cool down completely before frosting.
CHOCOLATE BUTTERCREAM & ASSEMBLY
- Melt the dark chocolate and heavy cream together in a heatproof bowl over a bain-marie (double boiler) or in the microwave in short bursts, stirring until smooth. Allow this chocolate mixture to cool completely to room temperature.50 g semi-sweet dark chocolate, 40 g heavy cream
- Sift the powdered sugar into a bowl to remove any lumps.90 g powdered sugar
- In your stand mixer (or using a hand mixer), cream the room temperature butter on medium/high speed for 4 minutes until it’s light, pale, and fluffy.50 g butter, ½ teaspoon vanilla extract
- Scrape down the sides of the bowl. Add the vanilla extract and the sifted powdered sugar to the creamed butter. Mix on low speed until just combined. Then, scrape the bowl again and mix for 2 more minutes on low/medium speed until smooth.
- Finally, add the cooled, melted dark chocolate mixture to the buttercream. Mix on low speed until fully incorporated and the buttercream is homogenous and smooth. Scrape down the sides once more and give it a final mix to ensure no streaks remain.
- Buttercream Consistency Tip: If your chocolate buttercream feels too soft or runny, place the mixing bowl in the fridge for 5-10 minutes. Then, give it a good mix again with your electric mixer before applying it to the cake; this will help it firm up.
- Once the banana cake is completely cool, spread the chocolate buttercream evenly over the top using an offset spatula or knife. Serve and enjoy!