Banana Bread Brownies combine the soft, moist texture of homemade banana bread with the easy-to-serve shape of dessert bars. Made with four ripe bananas, sour cream, butter, and vanilla, these tender squares are finished with a rich brown butter frosting that adds warm, nutty flavor.
They’re an excellent way to use overripe bananas and make an easy banana dessert recipe for family gatherings, potlucks, afternoon treats, or whenever you’re craving something beyond traditional banana bread.
Why You’ll Love This Recipe
These bars are wonderfully moist thanks to ripe bananas and sour cream. The bananas provide natural sweetness and plenty of flavor, while butter gives the crumb a rich, tender texture.
The brown butter frosting is what makes them particularly memorable. Browning the butter develops a toasted, nutty aroma that balances the sweetness of the powdered sugar.
They’re also simple and family-friendly. Everything bakes in one 9×13-inch pan, and the finished banana bread bars can be sliced into smaller or larger portions depending on the occasion.
Ingredients
For the Brownies
- 1 cup (200g) granulated sugar
- 1 cup (240ml) sour cream or plain Greek yogurt
- ½ cup (113g) unsalted butter, softened
- 2 large eggs
- 4 ripe bananas, mashed, about 2 cups
- 2 teaspoons pure vanilla extract
- 2 cups (250g) all-purpose flour
- 1 teaspoon baking soda
- ¾ teaspoon salt
- ½ cup (60g) chopped walnuts, optional
For the Brown Butter Frosting
- ½ cup (113g) unsalted butter
- 4 cups (480g) powdered sugar
- 1½ teaspoons pure vanilla extract
- 3 tablespoons milk, plus more as needed
Instructions
- Preheat the oven to 350°F (175°C). Grease and flour a 9×13-inch baking dish or line it with parchment paper for easier removal.
- In a large mixing bowl, beat the granulated sugar, sour cream, and softened butter together until creamy and slightly fluffy.
- Add the eggs, mashed ripe bananas, and vanilla extract. Beat until the mixture is smooth and evenly combined.
- In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
- Gradually add the dry ingredients to the banana mixture. Mix just until no obvious streaks of flour remain. Avoid overmixing.
- Fold in the chopped walnuts, if using.
- Transfer the batter to the prepared baking dish and spread it into an even layer.
- Bake the Banana Bread Brownies for 25–30 minutes, or until a toothpick inserted near the center comes out clean or with a few moist crumbs.
- Place the pan on a wire rack and allow the brownies to cool completely before frosting.
- To prepare the frosting, melt the butter in a small light-colored saucepan over medium heat. Continue cooking for about 4–5 minutes, swirling or stirring occasionally, until the butter becomes golden brown and develops a nutty aroma. Watch carefully to prevent burning.
- Remove the browned butter from the heat and allow it to cool slightly.
- Whisk in the powdered sugar, vanilla extract, and milk until smooth. Add a little additional milk if necessary to achieve an easily spreadable consistency.
- Spread the brown butter frosting evenly over the completely cooled brownies.
- Allow the frosting to set slightly, then slice into squares or bars and serve.
Tips & Tricks
Use very ripe bananas for the strongest banana flavor. Bananas covered with plenty of brown spots are ideal because they’re sweeter, softer, and easier to mash.
Measure the mashed banana when possible. Banana sizes vary considerably, and approximately 2 cups gives the recipe the intended moisture level.
Don’t overmix after adding the flour. Stir only until the dry ingredients disappear to keep your moist banana brownies tender rather than dense or tough.
Plain Greek yogurt can replace the sour cream if that’s what you have available.
If adding walnuts, toast them briefly before folding them into the batter for deeper nutty flavor.
Use a light-colored saucepan when browning the butter. It makes it much easier to see when the milk solids turn golden rather than accidentally burning them.
Most importantly, cool the bars completely before adding the frosting. Frosting warm brownies can cause the brown butter icing to melt.
Details
Prep Time: 20 minutes
Cook Time: 25–30 minutes
Cooling Time: Approximately 1 hour
Total Time: Approximately 1 hour 50 minutes
Yield: 16–24 bars
Category: Dessert
Method: Baking
Cuisine: American-Inspired
Difficulty: Easy
Dietary Notes: Vegetarian, halal-friendly when prepared with suitable vanilla extract and ingredients
Notes
Plain Greek yogurt can be substituted for sour cream in equal amounts.
Walnuts are optional and can simply be omitted for nut-free bars. Pecans also work well if you want a different nutty flavor.
For especially clean slices, refrigerate the frosted bars briefly and wipe your knife between cuts.
The brown butter frosting is quite sweet and rich. If you prefer less frosting, you can prepare a smaller batch or apply a thinner layer.
Serve these bars on their own, alongside coffee or tea, or with fresh banana slices for an easy dessert.
Nutrition
Approximate nutrition per serving when divided into 20 bars:
Calories: 300–350 kcal
Protein: 3–5 g
Carbohydrates: 50–58 g
Fat: 11–15 g
Nutrition information is an estimate and will vary according to portion size, frosting quantity, sour cream or yogurt, and whether walnuts are included.
FAQ
What are Banana Bread Brownies?
Banana Bread Brownies are soft banana dessert bars baked in a rectangular pan and cut into squares. They have the moist, tender qualities of banana bread but are served like brownies and finished here with brown butter frosting.
How ripe should bananas be for banana brownies?
Very ripe bananas are best. Look for yellow bananas covered with brown spots or bananas that have turned mostly brown. They provide more sweetness, moisture, and banana flavor.
Can I use Greek yogurt instead of sour cream?
Yes. Plain Greek yogurt can replace the sour cream and still helps produce soft, moist banana bread bars.
Why did my banana bread brownies turn out dense?
Overmixing after adding the flour can contribute to a tougher or denser texture. Mix the dry and wet ingredients only until combined. Measuring the flour accurately also helps.
Can I make Banana Bread Brownies without walnuts?
Absolutely. The walnuts are completely optional and can be omitted without making other changes to the recipe.
Do I have to make brown butter for the frosting?
Brown butter gives the frosting its distinctive toasted, nutty flavor, but regular melted butter can be used when necessary. The finished frosting will simply have a milder flavor.
Storage
Store frosted Banana Bread Brownies in an airtight container in the refrigerator for up to 5 days. Let individual bars sit briefly at room temperature before serving if you prefer a softer texture.
For short-term storage, unfrosted bars can be kept tightly covered at room temperature for about 2 days.
To freeze, place unfrosted bars in a freezer-safe container with parchment paper between layers. Freeze for up to 3 months and thaw overnight in the refrigerator. For the best appearance and consistency, add fresh frosting after thawing.
Similar Recipes
Banana Bread Brownies with Brown Butter Frosting
Ingredients
For the Brownies
- 1 cup 200g granulated sugar
- 1 cup 240ml sour cream or plain Greek yogurt
- ½ cup 113g unsalted butter, softened
- 2 large eggs
- 4 ripe bananas mashed, about 2 cups
- 2 teaspoons pure vanilla extract
- 2 cups 250g all-purpose flour
- 1 teaspoon baking soda
- ¾ teaspoon salt
- ½ cup 60g chopped walnuts, optional
For the Brown Butter Frosting
- ½ cup 113g unsalted butter
- 4 cups 480g powdered sugar
- 1½ teaspoons pure vanilla extract
- 3 tablespoons milk plus more as needed
Instructions
- Preheat the oven to 350°F (175°C). Grease and flour a 9×13-inch baking dish or line it with parchment paper for easier removal.
- In a large mixing bowl, beat the granulated sugar, sour cream, and softened butter together until creamy and slightly fluffy.
- Add the eggs, mashed ripe bananas, and vanilla extract. Beat until the mixture is smooth and evenly combined.
- In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
- Gradually add the dry ingredients to the banana mixture. Mix just until no obvious streaks of flour remain. Avoid overmixing.
- Fold in the chopped walnuts, if using.
- Transfer the batter to the prepared baking dish and spread it into an even layer.
- Bake the Banana Bread Brownies for 25–30 minutes, or until a toothpick inserted near the center comes out clean or with a few moist crumbs.
- Place the pan on a wire rack and allow the brownies to cool completely before frosting.
- To prepare the frosting, melt the butter in a small light-colored saucepan over medium heat. Continue cooking for about 4–5 minutes, swirling or stirring occasionally, until the butter becomes golden brown and develops a nutty aroma. Watch carefully to prevent burning.
- Remove the browned butter from the heat and allow it to cool slightly.
- Whisk in the powdered sugar, vanilla extract, and milk until smooth. Add a little additional milk if necessary to achieve an easily spreadable consistency.
- Spread the brown butter frosting evenly over the completely cooled brownies.
- Allow the frosting to set slightly, then slice into squares or bars and serve.
Notes
Conclusion
Banana Bread Brownies are a delicious solution for those extra-ripe bananas sitting on the counter. The soft banana-packed bars are easy to bake in one pan, while the creamy brown butter frosting gives an otherwise simple dessert a rich, bakery-style finish.
Whether you leave them plain, add crunchy walnuts, or spread on a generous layer of frosting, these easy banana bars make a comforting dessert that’s simple enough for everyday baking.