These peanut butter banana brownies are everything you could want in a brownie and more!

From its decadent banana brownie base to its peanut butter swirls, this recipe is a keeper.

How to Make These Peanut Butter Banana Brownies

To make sure your peanut butter banana brownies turn out as amazing as possible, let’s walk through each step together! I’ve also included a video tutorial of the process below.

Step 1: Preheat the Oven & Prep the Pan

Preheat the oven to 350°F / 175°C and line and grease an 8 x 8-inch square pan with parchment paper. Set aside.

You can also use a 9×9-inch pan, but the brownies will be a bit thinner, and the bake time will be a bit shorter.

Step 2: Make the Banana Brownie Batter

Then the fun begins! Place the eggs, granulated sugar, and brown sugar in a large bowl and mix on high for 1 minute with a hand mixer or stand mixer.

The mixture should get lighter in color and look creamy. Whipping up the sugar and eggs will help give these brownies a crinkly, shiny top.

Add the mashed bananas, melted butter, and vanilla extract to the egg mixture.

Mix on a medium speed until the ingredients are combined.

Then sift the all-purpose flour, cocoa powder, baking powder, and salt in and mix on a low speed until just combined. The batter might be a little bit chunky from the bananas, but that’s ok!

Scrape the sides and bottom of the bowl with a rubber spatula to make sure all the ingredients are properly mixed together.

Fold in the roughly chopped chocolate chips with a rubber spatula until they’re evenly distributed.

Step 3: Swirl the Batter Together and Bake

Then pour the batter into the prepared pan. Heat up the peanut butter in the microwave for about 10 seconds, then drop spoonfuls of warm peanut butter on top of the brownie batter.

Use a butter knife or small offset spatula to swirl the peanut butter into the batter.

Bake for 37-42 minutes or until a toothpick inserted in the middle of the brownies comes out with a few moist crumbs.

In my oven, the sweet spot is 40 minutes, but every oven bakes a bit differently!

Step 4: Cool Fully Before Cutting

Remove the brownies from the oven and place them on a wire rack to cool. As challenging as it is, I highly recommend letting the brownies cool fully before cutting them. It makes them so much easier to cut!

You can also accelerate the cooling process by popping the pan in the freezer for about an hour.

Substitutions & Swaps in These Peanut Butter Banana Bars

This recipe uses quite a few ingredients and I know you might not have all of them on hand.

Or if you have food allergies or restrictions, I’ve got you covered. Below are some swaps and substitutions that can be made in this recipe.

• Brown Sugar – The mix of granulated and light brown sugar gives these brownies a crispy top and a wonderful flavor. You can use light or dark brown sugar.
• Unsalted Butter – You can use salted butter if you don’t have unsalted butter on hand. Just omit the salt that this recipe calls for.
• Vanilla Extract – The vanilla extract adds an extra little oomph of flavor and helps enhance the chocolate in these brownies, but it can be omitted if needed.
• All-Purpose Flour – You can use a gluten-free flour blend in place of the all-purpose flour in this recipe. Just be sure to use a good baking blend like King Arthur’s GF flour.
• Baking Cocoa Powder – I like to use natural, unsweetened baking cocoa in this recipe. However, Dutch-processed or dark baking cocoa can also be used.
• Peanut Butter – Creamy peanut butter works best, but you can use chunky if you want a little extra texture! Avoid using natural peanut butter, if possible, it’s runnier than regular peanut butter and can separate as the brownies bake.

Why is it Better to Use Overripe Bananas in This Recipe?

Most banana recipes insist on using only the ripest bananas, including this one. But why are overripe bananas better to bake with?

There are actually several reasons! The first is that as a banana ripens, more of its starch is converted into sugar. This creates sweeter, more tender baked goods.

Another benefit of baking with super ripe bananas is that they’re super easy to mash up. This helps these brownies have a uniform, even texture without any big chunks of banana.

Overripe bananas are also more aromatic and give baked goods a more intense banana flavor than yellow bananas.

The final and best reason (in my opinion) is that it uses up overripe fruit that would otherwise go to waste!

With all that in mind, this recipe will still turn out if you use yellow bananas. It just won’t have as intense of a banana flavor.

Baking Hack: How to Quickly Ripen Bananas

If you only have yellow bananas and want that intense banana flavor, don’t worry!

You can easily turn yellow bananas brown in a matter of minutes. Preheat your oven to 300 F / 150 C and place the unpeeled bananas on a foil-lined baking sheet.

Bake them for about 15 minutes, or until the banana skin is uniformly dark in color.

Let them cool on the pan for 10 minutes, then carefully peel and mash them.

I use this hack all the time and it works like a charm.

Doubling this Peanut Butter Banana Brownie Recipe

If you want to double this recipe, go for it! Simply double the ingredients and make as instructed.

I recommend baking a double batch in a 9 x 13-inch pan to help them bake through properly. Bake the brownies at 350 F / 175 C for 40-50 minutes.

Making These Peanut Butter Banana Brownies in Advance

These brownies can be stored at room temperature for up to 5 days. Store them in an airtight container to keep them fresh.

They can also be stored in the fridge. I like them best when they’re cold and straight out of the fridge.

You can also freeze these brownies for up to a month. Freeze them uncut on a sheet pan until they are firm to the touch, then wrap them in a layer of plastic wrap and then foil.

When you’re ready to eat the frozen brownies, place them in the fridge overnight, then unwrap and enjoy the following day.

How to Make the Best Peanut Butter Banana Brownies

• Use super-ripe bananas! They’re sweeter and will give these brownies an amazing flavor.
• Make sure you properly measure your flour! I like to use a scale, but the fluff and level method works great too.
• Bake these brownies in a metal pan, not a glass pan, if possible. Glass gets hotter than metal pans. If you must bake these in a glass pan, bake them at 325 F.
• Chill these brownies before cutting into them. It makes them so much easier to cut.
• Use a warm, sharp knife to get clean slices. Fill a tall cup with hot water and dip a sharp knife into it. Dry the knife fully, then make a slice. Repeat with each cut and wipe the blade clean after each cut.
• If you want to make this recipe in a 9 x 13-inch pan, double the recipe and bake at 350 F for 40-50 minutes.

Let Me Know What You Think!

If you try this recipe for peanut butter banana brownies, I’d love to hear what you think of it!

Please leave a rating and let me know your thoughts by sharing a comment below.

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