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We enjoy every last bite of these cake-like banana bread bars because they never last long when I make them. The brown butter frosting is only 4 simple ingredients and makes them outstanding. You can customize the bars by adding nuts or chocolate chips instead of frosting, and I like to cut them into small squares for a bite size after school treat.
How to Make Banana Bread Brownies:
Mix we Ingredients: Cream butter and sugar: Beat in the sour cream and eggs, bananas and vanilla extract.
Add dry ingredients: flour, baking soda, salt, and mix just until moistened. Stir in walnuts, if using.
Bake: Pour batter into a 9×13 inch baking pan or half sheet pan. For a 9×13’’ pan, bake for 23-28 minutes or until a toothpick inserted in the center comes out clean or with few crumbs.

Make the glaze: Heat butter over medium heat and allow it to come to a simmer until it turns a delicate brown (watch carefully so you don't burn the butter). Remove from heat immediately. Whisk in the powdered sugar, vanilla extract and milk until smooth.
Pour Glaze over Bars: This is easiest when the bars are warm. Spread gently with the back of a spoon.

Recipe Variations:
- Add nuts: add chopped walnuts or pecans to the batter before baking.
- Add chocolate chips: add mini milk or semi sweet chocolate chips.
- Change the frosting: I love the brown butter frosting but this cream cheese frosting would also be delicious.
- Healthier banana bread bars: cut the sugar in half for a lighter version and use 3-4 Tbs of butter for the frosting instead of 6.
Make Ahead And Freezing Instructions:
To make ahead: bake and frost them one to two days ahead of time. Store them covered, in the refrigerator.
To freeze: allow them to cool completely and freeze them frosted or unfrosted right in the pan. Cover them well with plastic wrap and aluminum foil before freezing and freeze for up to 3 months. Allow to thaw completely before serving.
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Banana Bread Brownies
Ingredients
For the Banana Bread Bars:
- 1-1/2 cups granulated sugar
- 1 cup plain Greek yogurt, (or sour cream)
- 1/2 cup butter, softened
- 2 large eggs
- 3-4 ripe bananas, mashed
- 2 teaspoons vanilla extract
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- 3/4 teaspoon salt
For the Glaze:
- 4 Tablespoons butter
- 2 cups powdered sugar
- 1 teaspoon vanilla extract
- 1-2 Tablespoon milk
Instructions
- Preheat oven to 375 degrees F and grease a 9×13 inch pan with non-stick cooking spray.
- In a large bowl, cream together the sugar and butter. Beat in the sour cream and eggs, bananas and vanilla extract.
- Add the flour, baking soda, salt, and mix just until moistened. Stir in walnuts, if using.
- Spread batter evenly into prepared pan and bake for 23-28 minutes or until a toothpick inserted in the center comes out clean, or with few crumbs. Make frosting while the bars bake.
For the Brown Butter Frosting:
- Heat the butter in a large skillet over medium heat. Allow it to come to a simmer until it starts to turn a delicate brown and has a nutty aroma (watch carefully so you don't burn the butter!) Remove from heat immediately.
- Whisk in the powdered sugar, vanilla extract and 1 tablespoon of milk until smooth. (Add a little more powdered sugar, or milk, if needed to thicken or thin the frosting). Pour the warm frosting over the warm bars. Spread gently with the back of a spoon.
Notes
- Add nuts: add chopped walnuts or pecans to the batter before baking.
- Add chocolate chips: add mini milk or semi sweet chocolate chips to batter before baking.
- Change the frosting: I love the brown butter frosting but this cream cheese frosting would also be delicious.
- Healthier banana bread bars: cut the sugar in half for a lighter version and use 3-4 Tablespoons of butter for the frosting instead of 6.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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I originally shared this recipe June 2017. Updated January 2021.
Process photos by Nikole from The Travel Palate.




Yes! A really good brownie banana cake that was a huge hit with all my family. Moist, delicious and I didn’t even ice them, just put extra chocolate chips and walnuts on top. Yummy! Ten stars!
I made these banana bread brownies last night…. they are quite possibly one of my top 5 desserts of all time!!!! SO DELICIOUS!!!!!! I will continue to make and enjoy this dessert! Thank you.
This recipe is fantastic! The banana brownies were very moist and delicious. I cut the recipe in half because I was cooking for 2 but it did not negatively impact the taste. Next time though I will put a little less powdered sugar in the frosting because mines was kind of thick. Still delicious though!
OMG these brownies are awesome!!! Thank you for the recipe!!
I put my overly ripe bananas in the freezer when they get to the point I can’t or don’t have time to use them. I’m assuming the thawed bananas would be fine to use in this recipe?
Yes, that’s fine!
Absolutely delicious and simple to make! I added a swirl of Nutella after frosting them in stead of adding choc chips to the batter! Perfection 🤩 I didn’t have the full cup of sour cream so I replaced with 1/3 sour cream 1/3 of Mayo 1/3 of applesauce. Turned out super moist and flavorful.
Fabulous!!
These were a big hit! I used black walnuts. They freeze nicely.
The banana bread itself is amazing, however, the icing is gritty and tastes of powder sugar. When it dries it gets crumbly and stiff. Better off frosting with a creamy cream cheese frosting of your choice.
Very moist and delicious. My new favorite banana bar recipe!
Made these to help get rid of some over-ripe bananas, and yum! I only made half the icing recipe to use more as a drizzle, but honestly it doesn’t even need it. Next time I may try in my mini muffin pan and toss in some mini chocolate chips.
This is the absolute best banana brownie ever. So flavorful and moist. Awesome 👏
Made this recipe but sprinkled 1/8 cup cocoa powder on top of batter & swirled it thru batter with a knife. Cut back sugar to 1 cup.
Great recipe
Thank you for sharing!