Best-Ever Banana Cake With Peanut Butter Frosting

It might look like I’m on a “peanut butter and banana” roll (see these cream puffs), but I actually first made this banana cake with peanut butter frosting at the very beginning of the quarantine.  Yep, back in March 2020 when we thought we were having a little two-week blip. 

Sighhh, those were simpler times….

This cake is perfect for using up all those overripe bananas sitting on your counter, but when you’re like UGH I cannot deal with more banana bread!

One important note, this is not the healthiest form of banana cake, but it IS maybe the best banana cake recipe out there.

And then pair that banana cake with AMAZEBALLS peanut butter frosting, and you have a total winner.  Childhood, in cake form.

Preheat the oven to 350°F and grease a 9×13 inch pan.  I’ve also made this in two 8-inch rounds (plus a little ramekin for my own pleasure).  I’m showing photos from both below.

Start by mashing the bananas in a bowl and setting aside. In a stand mixer (with paddle attachment) or with a handheld electric mixer, cream the butter and sugars together until well-combined and fluffy, about 2 minutes.

Add the eggs and vanilla and blend together, scraping down the sides of the bowl as necessary.  Then add the mashed bananas and mix together.

With the mixer on low, add the dry ingredients (flour, baking powder, baking soda, cinnamon, and salt) along with the buttermilk in three additions, alternating between the wet and dry. 

Mix until *just* incorporated—don’t overmix!  A few lumps are totally fine.

Add the peanuts if you’re using them, and give a couple light pulses to stir them in.

Spread the batter into your prepared pan(s) and bake for 40-50 minutes; if you’re doing two smaller round pans it will be more like 30-35. 

Baking times will depend on your oven, so keep an eye on yours and if it starts to brown too soon you can loosely cover it with aluminum foil.  When it’s done, a toothpick inserted should come out clean with a few crumbs.

Remove the cake from the oven and set it on a wire rack, letting it cool completely.

I love to cover this best-ever banana cake with my absolute favorite peanut butter frosting, and that link goes more in-depth on making it.  But the technique is simple.  The secret is in having a much higher peanut butter ratio than most buttercream frostings.

To make the frosting, beat the butter in your stand mixer or with an electric hand mixer, then add the peanut butter and beat for about 30 seconds to combine it. Add the powdered sugar and sea salt and beat until fluffy.  If needed, add a tablespoon of cream or milk (or more) to get the right texture. 

Personally I often add some more sea salt for a nice salty balance.  Frost the cake, and either serve immediately or cover.  

You can store leftover cake in the refrigerator for up to 5 days.  But honestly, if you still have leftovers after 5 days…you’re doing something wrong.

This might be the best banana cake recipe ever…and paired with this peanut butter frosting it’s as all-American of a combo as you could want! 

Other desserts you’ll love:

• Classic Hummingbird Cake with Cream Cheese Frosting
• Fresh Grapefruit Cake with Mascarpone Frosting
• Dark Chocolate Bundt Cake With Peanut Butter Glaze
• “Elvis” Banana, Salted Honey, & Peanut Butter Cream Puffs
• Banana Cake with Caramel Icing

Cake adapted slightly from Sally’s Baking Addiction

Pin for later!

Best-Ever Banana Cake With Peanut Butter Frosting

Yield: 1 9x13 cake or 1 double-layer round one

Prep Time: 10 minutes

Cook Time: 45 minutes

Additional Time: 1 hour

Total Time: 1 hour 55 minutes

Print

Ingredients

• CAKE
• 3/4 cup (170g) of unsalted butter, softened to room temperature
• 1 cup (200g) of granulated sugar
• 1/2 cup (100g) of packed light or dark brown sugar
• 3 large eggs, at room temperature
• 2 teaspoons of pure vanilla extract
• 3 large very ripe bananas (about 1 1/2 cups mashed)
• 3 cups (375g) of all-purpose flour (spoon & leveled)
• 1 teaspoon of baking powder
• 1 teaspoon of baking soda
• 1/2 teaspoon of ground cinnamon
• 1/2 teaspoon of salt
• 1 1/2 cups (360ml) of buttermilk, at room temperature
• Optional:  1/2 to 1 cup of chopped peanuts (great texture, but increases calories)
• FROSTING
• 1 cup of peanut butter (I used Skippy creamy); see notes
• 1/2 cup of softened butter (I used unsalted)
• 1 cup of powdered sugar
• A pinch of sea salt
• 1-2 tablespoons of heavy cream (or 2% or whole milk)

Instructions

1. Preheat the oven to 350°F and grease a 9×13 inch pan.  I've also made this in two 8-inch rounds (plus a little ramekin for my own pleasure).
2. To make the cake, mash the bananas in a bowl and set aside. In a stand mixer (paddle attachment) or with a handheld electric mixer, cream the butter and sugars together until well-combined and fluffy (about 2 minutes).
3. Add the eggs and vanilla and blend together, scraping down the sides of the bowl as necessary.  Then add the mashed bananas and mix together.
4. With the mixer on low, add the dry ingredients (flour, baking powder, baking soda, cinnamon, and salt) along with the buttermilk in three additions, alternating between the wet and dry.  Mix until *just* incorporated---don't overmix!  A few lumps are totally fine.
5. Add the peanuts if you're using them, and give a couple light pulses to stir them in.
6. Spread the batter into your prepared pan(s) and bake for 40-50 minutes; if you're doing two smaller round pans it will be more like 30-35.  Baking times will depend on your oven, so keep an eye on yours and if it starts to brown too soon you can loosely cover it with aluminum foil.  When it's done, a toothpick inserted should come out clean with a few crumbs.
7. Remove the cake from the oven and set it on a wire rack, letting it cool completely.
8. To make the frosting, beat the butter in your stand mixer or with an electric hand mixer, then add the peanut butter and beat for about 30 seconds to combine it.  Add the powdered sugar and a pinch of salt and beat until fluffy.  Add 1 tablespoon of the cream or milk, as needed to get the right texture.  I often add some more sea salt for a nice salty balance.
9. Frost the cake, and either serve immediately or cover.  You can store leftover cake in the refrigerator for up to 5 days.

Notes

• A combo of buttermilk and Greek yogurt can work well too. 
• Don't use natural peanut butter (the texture is wrong).