Peanut Butter Banana Brownies

We always end up with overripe bananas in our household, so I wanted to find a way to incorporate those into a baked treat that satisfies chocolate cravings. Hence the idea for these peanut butter banana brownies was born!

These flavors go SO well together: the fudgy chocolate brownie (with pools of melty chocolate chips), the sweet banana, and the salty peanut butter swirl on top.

banana brownies on parchment paper with a spoonful of peanut butter

Banana Brownies with Peanut Butter Swirl

Bananas are a popular addition to baked goods, especially as a way to add sweetness naturally. They’re delicious in banana bread, cakes, pies, and cookies. But for some reason, I hadn’t tried them in brownies until recently.

It makes sense that bananas would be good in brownies, though – they’re sweet, pair well with chocolate, and help keep the brownies nice and fudgy. And with the addition of the peanut butter swirl here, they’re absolutely irresistible.

I shared these with some family that was in town for a taste test, and they were a big hit!

Recipe Ingredients

To make these banana brownies, you’ll need:

  • ripe bananas: You’ll need 2 small-to-medium bananas here. Very ripe or overripe bananas are best, as they’ll be easier to mash and they’ll make the brownies taste sweeter. (If your bananas are pretty brown/spotty, transfer them to the fridge in an airtight bag so they’ll keep longer until you’re ready to bake.)
  • all-purpose flour
  • butter: Because we’re using ripe bananas in these brownies, we don’t need as much butter (compared to typical brownies). But we’re still using some to make sure they’re still plenty rich and moist.
  • sugar: Again, thanks to the bananas, we don’t need as much sugar as typical brownies would call for. A combination of white and brown sugar gives just the right amount of sweetness, and the brown sugar enhances the fudgy texture.
  • eggs: For structure and rise. Make sure they’re at room temp!
  • cocoa powder: Unsweetened cocoa powder gives the brownies that rich, chocolatey flavor we know and love!
  • vanilla extract
  • chocolate chips: I added chocolate chips for even more chocolatey goodness. Any kind should work: dark, semisweet, or milk chocolate.
  • peanut butter: For the delicious, slightly salty swirl on top! You can skip this if you want – it shouldn’t affect the actual baking of the brownies. (I haven’t tested these with natural peanut butter, but I think it should work as long as you stir it well first. Let me know if you try it!)
  • baking powder
  • salt

If you have extra overripe bananas, try these hazelnut banana bread bars!

stack of brownies with banana, peanut butter, and chocolate chips

How to Make Banana Brownies

In terms of the baking process, these are pretty similar to your standard brownies, with the exception of adding mashed banana and the peanut butter swirl on top.

You start by combining all the dry ingredients (including the cocoa powder) in a medium-sized bowl and whisking them together. Set aside for now.

In a separate large mixing bowl, combine hot melted butter with the sugars (white and brown) and whisk well. Add the eggs, mashed banana, and vanilla extract, then whisk again until well-mixed.

Then, sift in the mixed dry ingredients (this helps prevent clumps) and stir with a rubber spatula until almost combined.

Pour in chocolate chips and fold them in with the spatula, until there are no more flour streaks.

Pour the mixture into an 8x8in square baking dish lined with parchment paper. Next, it’s time to create the peanut butter swirl!

Add a Peanut Butter Swirl

Microwave peanut butter in a microwave-safe bowl in 30-second increments on 50% power, until smooth and drippy. Dollop spoonfuls over different spots of your brownie batter.

Then, using a butter knife, swirl through the dollops (as if you’re drawing wide squiggles), creating a swirled pattern. Try not to press the peanut butter down too deep into the batter.

brownie batter with peanut butter swirl in a glass baking pan

Then, bake at 350 degrees Fahrenheit for 25-30 minutes. Check with a toothpick – it should come out with just a few fudgy crumbs.

Allow the brownies to cool, then remove them from the baking pan (using the parchment paper) and slice with a sharp knife.

sliced brownies on parchment paper

Tips for Slicing Brownies

If you want to make cleaner slices, be sure to let your brownies cool completely first. Running your knife under hot water (and drying it) first will also help make the slices cleaner.

Lining your baking pan with parchment paper is also essential, as it allows you to remove the uncut brownies from the pan cleanly. Once they’re out of the pan, they’re much easier to slice.

Storage Tips

Store leftover brownies in an airtight container on the counter (at room temperature) for up to 3 days.

banana brownies with peanut butter swirl and chocolate chips

Peanut Butter Banana Brownie Toppings & Mix-Ins

Here are a few different ways to change up this brownie recipe:

  • Add chopped nuts or shredded coconut to the batter
  • Use another nut butter, like almond butter, for the swirl on top instead
  • Or, add a Nutella or Biscoff spread swirl
  • Top with chopped peanuts
banana brownies with peanut butter swirl

This is definitely my new go-to brownie recipe – especially when I have browning bananas waiting the counter, practically begging to be used. In fact, it might be time to whip up another batch right now. 🙂

If you try these peanut butter banana brownies, I’d love if you shared your thoughts with a rating and comment below!

More delicious baked desserts:

banana brownies with peanut butter swirl

Peanut Butter Banana Brownies

These peanut butter banana brownies are fudgy and delicious, made with sweet overripe bananas, chocolate chips, and a lightly salty peanut butter swirl on top!
Prep Time 15 mins
Cook Time 25 mins
Total Time 40 mins
Course Dessert
Cuisine American
Servings 9 brownies

Ingredients
  

For the Banana Brownies

  • ½ cup all-purpose flour (spooned and leveled)
  • cup unsweetened cocoa powder
  • ½ tsp baking powder
  • ¼ tsp salt
  • ¼ cup unsalted butter
  • ¼ cup white granulated sugar
  • ½ cup brown sugar (packed)
  • 2 large eggs (at room temperature)
  • ½ cup mashed banana (About 2 small-to-medium bananas. Ripe bananas are best.)
  • 1 tsp vanilla extract
  • cup chocolate chips (I used semisweet)

For the Peanut Butter Swirl

  • ½ cup peanut butter

Instructions
 

  • Preheat your oven to 350° Fahrenheit (176° Celsius). Line an 8x8in baking pan with parchment paper and set aside.*
  • Whisk all the dry ingredients together (flour, cocoa powder, baking powder, and salt) in a medium bowl. Set aside.
  • Microwave butter in a microwave-safe bowl in 30-second intervals at 50% power until melted and hot. Pour into a large mixing bowl.
  • Add the white and brown sugars to the melted butter and whisk vigorously. Add the eggs, mashed bananas (mashed in a separate bowl and measured before adding), and vanilla extract. Whisk again until well-mixed.
  • Sift in the dry ingredients (that you combined earlier) and gently stir with a rubber spatula until almost combined. Don't over-mix.
  • Gently fold in the chocolate chips until no more flour streaks remain. Pour the batter into your lined baking dish.
  • Add the peanut butter swirl: Microwave peanut butter in a microwave-safe bowl in 30-second intervals at 50% power until smooth and drippy. Dollop spoonfuls over the brownie batter in different places. Using a butter knife, swirl through the peanut butter as desired to create a pattern. (Try not to push the peanut butter down below the surface too much.)
  • Bake for 25-30 minutes until a toothpick pressed into the center comes out with just a few fudgy crumbs.
  • Allow the brownies to cool. Remove them from the baking pan (by pulling up on the edges of the parchment paper) and slice with a sharp knife.

Notes

*When lining your baking pan with parchment paper, it helps to spray cooking spray or grease the pan first, then place the parchment paper on top – it will stick better.
Storage Tips: Store leftover brownies in an airtight container on the counter (at room temperature) for up to 3 days.
Keyword banana, brownies, chocolate, peanut butter

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