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 will be taking the place of all banana recipes. I love all things browned butter and this did not disappoint. Frosting was deliciously fluffy which contrasted nicely with the not overly sweet banana bar.
Perfectly moist and delicious! Never making regular banana bread again after trying these. Friends and family loved!!
Omg I’m a pastry chef so I usually don’t indulge, however I wanted to try something new to add to my rotation. This is the FIRST time I’ve not been able to stop myself from eating a dessert. Usually I’m satisfied with 1 serving of whatever I’ve made. I’ve eaten 3 of these. They’re that good.
BEST THING IVE EVER MADE !!
One of my coworkers said “this is so good, gonna have to call my momma”
Pretty much sums it up
i don’t even like bananas or banana bread but these were absolutely amazing and all my friends loved them!! i used greek yogurt instead of sour cream because i didn’t have any and they came out perfect!! thank you for this recipe, will be making again and again in college
That brown butter flavor!!! Just too good to stop eating it. (Thanks for the instructions on how it bubbles and then foams!) Made it while staying with my daughter and her new baby! We all loved it! Will definitely make it again. I’ll add chopped toasted pecans.
Made these with Greek yogurt (was out of sour cream) and Bob’s 1:1 (blue bag). They were FANTASTIC! I was not expecting them to be so good, and the frosting was next level. I would actually love to try the frosting on some cinnamon rolls!
I made this recipe last night and this is the most delicious banana baked item I have ever had. It’s even good refrigerated and eaten cold. Definitely saving this as my go-to recipe whenever I have bananas to use up. Thank you for sharing this!
These turned out amazing! The banana flavor was great, and a lot of people enjoyed the frosting although they said it was a little too sweet. Is there any suggestions on how to cut back the sweetness a little?
PHENOMENAL!! I must warn you though…once you make these and share with others, people will BEG you to make more. I’m talking I brought these to work ONE time and people I don’t even know have stopped me and told me to make more and it was the best banana bars they’ve ever had. The only tweak I made was I used the extra mashed bananas I had and added it to the frosting!! Without the banana added, in my opinion, the frosting is too sweet but by adding them it makes the whole thing tie together! Amazing recipe and thank you for sharing!