This peanut butter banana cake, finished with a silky peanut butter buttercream, is one of the tastiest ways to use ripe bananas. Soft, moist layers and a rich peanut butter frosting make it a crowd-pleaser that’s simple enough for everyday baking but pretty enough for special occasions.
I keep a list of essential cakes on my site, and this easy peanut butter banana cake deserves a spot alongside them. The flavor balance—subtle banana, pronounced peanut butter, and tender cake texture—is hard to beat.
With a few pantry staples and ripe bananas, you can pull this together quickly. The recipe starts with a white cake mix that’s doctored up with real ingredients for a homemade flavor and texture, while keeping the process approachable and reliable.
How to make the best peanut butter banana cake layers
These cake layers are soft, tender, and perfectly balanced between banana and peanut butter. The method is straightforward: combine the wet ingredients, gently fold in the cake mix, and bake until just set. Using a boxed cake mix as the base keeps the batter forgiving while the added bananas, peanut butter, and dairy give the cake real depth and moisture.
Ingredients for Peanut Butter Banana Cake
You only need a handful of common ingredients to make these layers:
- 2–3 ripe bananas, mashed (about 3 small or 2 medium)
- 1/4 cup peanut butter
- 4 large egg whites, room temperature
- 3/4 cup buttermilk, room temperature
- 2/3 cup sour cream, room temperature
- 1/3 cup vegetable oil
- 1 tablespoon vanilla extract
- 1 box white cake mix
Basic directions: preheat the oven, whisk the wet ingredients together, sift and fold in the cake mix until just combined, divide into prepared pans, and bake until the centers are set. Allow the layers to cool completely before frosting.
Can I make this into cupcakes or a sheet cake?
Yes. This batter adapts well to different formats without changing ingredient proportions—only the baking time will vary. For cupcakes, fill 24 liners and bake 12–15 minutes. For a 9×13 sheet cake, bake 32–35 minutes. For three 6″ round pans, plan for about 30–32 minutes. Always test for doneness with a toothpick and avoid overbaking to keep the layers moist.
How to make easy peanut butter buttercream
This buttercream is creamy, smooth, and pairs perfectly with the banana-studded cake layers. It starts with a classic vanilla buttercream base, then gets boosted with Skippy creamy peanut butter for the best texture and flavor. The result is a spreadable frosting that holds shape for piping while remaining soft enough for smooth finishes.
Ingredients for the best peanut butter buttercream
Keep these ingredients on hand for a rich, silky buttercream:
- 1 1/2 cups unsalted butter, at room temperature
- 1 pinch salt
- 1 tablespoon vanilla extract
- 1/2 cup Skippy creamy peanut butter
- 1/2 cup heavy cream
- 7–8 cups powdered sugar, sifted as needed for consistency
Make the buttercream by whipping the butter until light, then add salt, vanilla, peanut butter, and cream. Gradually incorporate the powdered sugar on low speed, then whip on high for about two minutes to make it light and fluffy. Adjust cream or sugar to reach the desired spreadable consistency.
Tips for serving
If you want to garnish with fresh banana slices, slice them right before serving to prevent browning. Alternatively, use dried banana chips for a longer-lasting, decorative option. A light drizzle of melted peanut butter across the top adds shine and extra flavor.
Video of making a peanut butter banana cake
A short video accompanies this recipe on the original post, demonstrating assembly and finishing touches for the cake.
I hope you enjoy making this beautiful and delicious cake. If you bake it, I’d love to see your photos—share them on social media and tag the original author if you follow the recipe from the source.
Happy baking,
Mandy xo
Get the Recipe: The Best Peanut Butter Banana Cake with Peanut Butter Buttercream
Tender peanut butter banana cake layers paired with a soft and creamy peanut butter buttercream. Serves about 12 slices.
Ingredients
Peanut Butter Banana Cake
- 2–3 ripe bananas (3 small or 2 medium)
- 1/4 cup Skippy creamy peanut butter
- 3/4 cup buttermilk, room temperature
- 2/3 cup sour cream, room temperature
- 4 large egg whites, room temperature
- 1/3 cup vegetable oil
- 1 tablespoon vanilla
- 1 box white cake mix
Peanut Butter Buttercream
- 1 1/2 cups unsalted butter, room temperature
- 1 pinch salt
- 1 tablespoon vanilla
- 1/2 cup Skippy creamy peanut butter
- 1/2 cup heavy cream
- 7–8 cups powdered sugar
Garnish
- Melted peanut butter for drizzling (optional)
- Fresh banana slices, added just before serving
Instructions
For the Cake Layers
- Preheat the oven to 325°F (convection bake). Prepare two 8″ cake pans with baking spray, parchment rounds, or a light coating of shortening and flour.
- In a large bowl, whisk the mashed bananas, peanut butter, egg whites, buttermilk, sour cream, vegetable oil, and vanilla until combined. Sift in the white cake mix and fold gently until there are no streaks—avoid overmixing.
- Divide the batter evenly between the prepared pans. Bake 25–32 minutes, depending on oven and pan size, until the centers are set and a toothpick comes out clean. Cool completely, wrap, and chill or freeze briefly for easier handling.
For the Peanut Butter Buttercream
- In a stand mixer fitted with the paddle attachment, beat the butter until light and fluffy.
- Add salt, vanilla, peanut butter, and heavy cream; mix until combined.
- With the mixer on low, gradually add powdered sugar until incorporated. Increase speed and whip for about 2 minutes until the frosting is light and fluffy. Adjust with a tablespoon or two of heavy cream if the buttercream is too thick.
- Press down with a wooden spoon or spatula to release large air bubbles before assembling.
Assembly
- Place a small amount of buttercream on the cake board or serving plate to secure the first layer. Add the first cake layer and spread an even layer of buttercream.
- Top with the second layer, press gently, and apply a thin crumb coat. Chill for 5–10 minutes to set.
- Finish with a final layer of buttercream, smooth or decorate as desired. Drizzle with melted peanut butter and arrange fresh banana slices just before serving.
Author: Mandy Merriman – Baking with Blondie