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Banana Bread Brownies

These banana bread brownies with brown butter frosting are nothing short of sinful! They’re fluffy, moist and packed with crunchy walnuts and bold banana flavor. The rich frosting on top makes them next level delicious!

banana bread brownies on plate with fork
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Frosted Banana Bread Brownies

In my kitchen, browning bananas are a recurring eye sore. So, determined to put the bananas to good use, I’ve finally pinpointed my ultimate banana dessert for those over-repined bananas.

While I absolutely love an easy banana cream pie, these brownies are my recent go-to dessert!

By creating a batter that is more brownie than banana bread, this recipe will stun your taste buds. Moist and flavorful, the brownie is a treat in itself. But then there’s the brown butter frosting that knocks this dessert out of the park.

banana bread brownie ingredients

How to Tell if Bananas are Ripe?

The key to super moist, sweet and flavorful banana bread brownies is using bananas that have fully ripened. Your bananas should be covered in brown spots and soft to the touch. The riper the banana, the sweeter the brownies!

Brown Butter Frosting

I must admit, browning butter has been a baking fear of mine. Every bakers’ notes emphasize watching the butter closely because when it turns golden brown, it turns quickly. After learning how to make brown butter successfully, I can now tell you with full faith that it’s not so bad. Yes, you should watch the butter and stir it constantly, but it’s nothing to fret over!

Once the butter has browned, then you’ll mix it together with the remaining frosting ingredients until smooth. The consistency will be thinner (more like a glaze than a frosting to be honest), which makes it perfect for pouring over the warm bars. The frosting will thicken fast, so it’s important to move quickly!

banana bread brownies in baking sheet


  • Fold chocolate chips into the batter for an extra sweet taste (use 1/2 to 1 cup).
  • Swap walnuts for pecans.
  • Use Greek yogurt in place of sour cream to lighten it up a bit.
  • Add in a teaspoon of cinnamon.
  • Top with cream cheese frosting, sour cream frosting or even a coconut pecan frosting.
  • You can make these into thinner banana bars by using a larger 12×18″ baking sheet.

How to Store Banana Brownies

Once the brownies have cooled, store them in a covered container at room temperature. They will stay fresh for up to 3 days.

You may also freeze the brownies if you prefer. Flash freeze them first on a baking sheet for about an hour, then stack in a freezer container with a piece of parchment paper in between each layer. Let the brownies sit on the counter at room temperature for about an hour before serving.

banana bread brownies on plate with fork

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banana bread brownies on plate with fork

Banana Bread Brownies

5 from 4 votes
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Author: Jamielyn Nye
These banana bread brownies with brown butter frosting are nothing short of sinful! They're fluffy, moist and packed with crunchy walnuts and bold banana flavor. The rich frosting on top makes them next level delicious!
Prep Time: 20 mins
Cook Time: 20 mins
Total Time: 40 mins
Servings: 24


Brownie Batter:

  • 1 ½ cups granulated sugar
  • 1 cup sour cream
  • ½ cup butter , softened
  • 2 large eggs
  • 3 ripe bananas , mashed
  • 2 teaspoons vanilla extract
  • 2 cups all-purpose flour
  • 1 teaspoon baking soda
  • ¾ teaspoon table or fine sea salt
  • 1/2-1 cup chopped walnuts , you can omit if desired

Brown Butter Frosting:

  • ¼ cup butter
  • ¼ cup light brown sugar
  • 3 Tablespoons milk
  • 1 ½ teaspoons vanilla extract
  • 2 cups confectioner’s sugar


  • Heat oven to 375°F. Line a 9×13" pan with parchment paper, or grease and flour. Set aside.
    pan with flour dusted inside
  • In a large bowl, beat together sugar, sour cream, butter, and eggs until creamy. Blend in bananas and vanilla extract.
    sour cream and sugar in glass bowl
  • In separate bowl, whisk (or sift) the flour, baking soda and salt together.
    flour and sugar in glass bowl
  • Add the flour to the banana mixture and mix just until combined. Stir in walnuts if desired. Spread batter evenly into pan and bake for 20 to 25 minutes or until a toothpick comes clean.
    banana bread brownie batter in pan
  • Prepare the frosting as the brownies bake by heating butter in a large saucepan over medium heat. Add the brown sugar to the melted butter and bring to a boil, stirring continuously for about 2 minutes. Remove from heat immediately.
    brown butter glaze in pot
  • Add powdered sugar, vanilla extract and milk. Whisk together until smooth (it will be thinner than frosting). Using a spatula, spread the brown butter frosting over brownies. This is best done when both ingredients are warm. Sprinkle chopped walnuts on top if desired.
    spreading glaze on top of banana brad brownies
  • Slice brownies into 24 squares. Serve warm, room temperature or even cold!
    banana bread brownies on plate with fork



  • Add chocolate chips to the batter before baking. Start with 1/2-1 cup.
  • Use Greek yogurt in place of sour cream. 
Storage: Allow brownies to cool and store in a covered container for 3 days.
Freezer Instructions: Place brownies on a baking sheet and freeze for 1 hour, or until hardened. Then place in a freezer container (you can stack with a piece of parchment paper in between each layer). Remove an hour before serving.


Calories: 257kcal | Carbohydrates: 37g | Protein: 2g | Fat: 11g | Saturated Fat: 5g | Cholesterol: 34mg | Sodium: 184mg | Potassium: 113mg | Sugar: 26g | Vitamin A: 270IU | Vitamin C: 1.4mg | Calcium: 27mg | Iron: 0.8mg

Nutrition provided is an estimate. It will vary based on specific ingredients used.

Course: Dessert
Cuisine: American

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