Brown Butter Frosted Banana Bread Bars
These banana bread bars are so quick and easy to make and it’s the perfect way to use up those spotty ripe bananas! Plus, it’s made extra special with brown butter both in the batter and the frosting on top. It’s the perfect dessert for a crowd and everyone LOVES them!
How to make brown butter banana bread bars
Rather than just making brown butter frosting and calling it day, I decided to put brown butter both in the bars and in the frosting! So to make this recipe quick and simple, the butter is all browned at once.
This is both the butter for the batter and for the frosting. Once the big batch of butter is nice and browned, it’s divided in two.
First, 1/2 cup is poured out and reserved for the batter. The remaining brown butter goes into a mixing bowl. Then 2 tablespoons of extra butter are stirred in which helps the hot butter cool down faster.
This is important because the butter must be solid before making the frosting. So while the bars are being prepared, the frosting butter chills in the refrigerator.
By the time the bars are baked and cooling, the frosting butter should be at the perfect consistency! It’s mixed with powdered sugar, vanilla, and milk to make the most delicious brown butter frosting.
The frosting is spread over the slightly warm bars which allows it to ever-so-slightly melt into these delicious banana bread bars.
How to make brown butter
If you’ve never made brown butter before, check out my guide on how to make brown butter. It’s a quick and simple process but there are a few important things to note before diving right in!
Banana bread bars baking tips
These bars are SO easy to make, but here are a few tips to ensure yours turn out just right:
- Bananas – Measure the bananas to exactly 1 1/2 cups. Don’t go just by the amount (about 4 bananas) as this is just a suggestion to help you gauge how many you will need. Bananas come in many different sizes, so 4 bananas to you might be too much or too little. Mashing and then measuring is the best way to ensure accuracy every time.
- Brown Butter – All the flavor in brown butter is in the little brown bits that tend to sink to the bottom of the butter. So when pouring the butter into the batter, make sure to scrape in every last drop.
- Flour – I always say to measure the flour if you can. If a scale isn’t available, gently spoon the flour into a measuring cup and level it off for a light and fluffy cup of flour. Never scoop directly down into the flour as this packs it down into the cup, leaving you with way too much excess flour in the batter.
- Mixing – When mixing in the flour, don’t over work the batter. Mix just until it comes together, otherwise your bars will be tough rather than soft and tender.
Banana Bread Bars FAQs
I haven’t tested it myself, but I do think these bars could work really well with gluten free flour! Sub in a cup for cup gluten free baking flour and you’re good to go.
Yes, although a jelly roll pan is much more traditional to this type of bar. But if you do bake in a 9×13 dish, add on about 5 extra minutes and test in the center for doneness.
If you’re just short of 1 1/2 cups, you can supplement the rest with sweetened or unsweetened apple sauce.
Stored in an air tight container, these bars can keep at room temp for a couple days. But any longer than that and they will need to be placed in the refrigerator where they will keep for about a week.
Yes, the recipe can be halved and baked in an 8×8 pan. I suggest about 20 minutes.
Use my popular chocolate chip banana bread recipe instead! Feel free to brown the butter for that batter as well.
For more banana recipes, check out my:
- Chocolate Chip Banana Bread
- Banana Cake with Peanut Butter Chocolate Frosting
- Banana Coffee Cake
- Peanut Butter Banana Upside Down Cake
Make sure to tag me @butternutbakery on Instagram and leave a review below if you make these banana bread bars. To pin this recipe and save it for later, you can use the button on the recipe card, the buttons above or below this post, or on any of the photos above. Happy baking!
Watch how to make these banana bread bars:
Brown Butter Frosted Banana Bread Bars
- Total Time: 1 hour 15 minutes
- Yield: 24 bars
Description
These banana bread bars are the perfect way to use up those spotty ripe bananas sitting on your counter! They’re also made extra special with brown butter both in the batter and in the sweet frosting on top.
Ingredients
Banana Bread Bars
- 1/2 cup (110g) unsalted butter
- 1 cup (200g) granulated sugar
- 1/2 cup (105g) light brown sugar, packed
- 2 large eggs
- 1 cup (250g) sour cream
- 1 1/2 cups (385g) ripe banana, mashed (4-ish bananas)
- 1 tsp vanilla extract
- 1 tsp baking soda
- 1/2 tsp kosher salt
- 2 cups (265g) all purpose flour
Brown Butter Frosting
- 3/4 cup (170g) unsalted butter (+ 2 tbsp chilled)
- 3 cups (300g) powdered sugar
- 1 tsp vanilla extract
- 1/4 cup (60g) milk, room temp
Instructions
Banana Bread Bars
- Preheat the oven to 350F and grease an 11×15 jelly roll pan.
- Combining the butter from the banana bread bars and the butter for the frosting (minus the additional 2 tbsp) equates to 1 1/4 cup of butter. Add this butter to a saucepan over medium heat to brown.
- It will go from melted, to loud and bubbly, to quiet and foamy. Keep stirring until it turns a light amber color.
- Dividing the browned butter, measure out 1/2 cup for the banana bread bars and pour the remaining brown butter in a mixing bowl. Now drop in the extra 2 tablespoons of butter into the mixing bowl and mix to melt.
- Place the bowl of brown butter into the refrigerator as it needs to solidify for the frosting.
- Now pour the 1/2 cup of brown butter (reserved for the bars) into a seperate mixing bowl and whisk in the sugar and brown sugar.
- Then whisk in the eggs, followed by the sour cream, banana, and vanilla.
- Whisk in the baking soda and salt, followed by the flour.
- Pour the batter into the prepped pan and spread even.
- Bake for 25-30 minutes.
- While the bars cool, make the frosting.
Brown Butter Frosting
- By now, the refrigerated bowl of brown butter should be solid but still soft.
- Using a hand or stand mixer with the whisk attachment, gradually mix in the powdered sugar one cup at a time, followed by the vanilla and milk.
- Spread the frosting over the slightly warm bars and allow them to cool at room temp for about 30 minutes. Then slice and enjoy!
Equipment
Buy Now → - Prep Time: 20 minutes
- Cooling Time: 30 minutes
- Cook Time: 25 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
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Meet Jenna
I’m the creator, baker, and photographer behind Butternut Bakery. Here I share desserts for every diet because I believe everyone should have a chance to indulge!
This was FANTASTIC!! Easy to make and mouthwatering delicious. The brown butter made it over the top amazing.
I brought it to work and everyone was fighting over seconds. I would rate this 10 stars if I could.
Made these for the first time and my family was absolutely obsessed. The brown butter frosting is so good. I absolutely love all of her recipes.
Made these last week, I subbed Greek yogurt for the sour cream and added mini chocolate chips. They’re really good, will definitely make again.
O.M.G. These are amazing! I’ve made them twice now and they were a hit both times! They are heavy in butter and sugar so be prepared to indulge because they are so worth it. Thank you Jenna for sharing your recipe 🙂
Best EVERRRR!! I did not change a thing. Oh my goodness these are addicting. My family loves this recipe! How long would I cook and at what temperature would I cook these if I used to loaf pans?
I have made this numerous times and loved everything about It! But this time i only have salted butter? Do i make It the same or leave out the salt in the batter?
I just made this & it is the best banana dessert I ever made!! I’ll definitely try make other desserts with your recipe, thanks for sharing you recipe!
These are so good! After reading the comments about them being overly sweet, I made some adjustments that I think are necessary. I increased the salt in the batter to 3/4 tsp, and I added about 1/4 tsp of salt to the frosting (it really needs salt). I also decreased the powdered sugar to 2 1/2 cups because some folks said it was too sweet. They turned out perfect. That frosting is the best! I’d put it on anything.
This was such a nice recipe! I like to roast the bananas in the air fryer for about 15 minutes so that I get a more intense flavor. I also added some roasted walnuts to the batter. Thanks so much for another delicious recipe.
These were absolutely incredible! I can not stop eating them and I have everyone at my office begging me to make more. I followed the recipe exactly and they came out perfect. They were baked to perfection at just 25 minutes, toothpick came out clean. I think next time I may add some more banana to the batter and maybe a pinch of cinnamon. I know some people said the frosting was too sweet in other reviews, but I have to disagree, it was perfect but I do love sweet stuff. Several people told me the frosting was their favorite part. I also added chopped pecans and some flaky sea salt to the top, which may have cut the sweetness. I will 100% be making these bars over and over again. Thank you!