These Banana Bread Brownies are soft, moist, and full of rich banana flavor, topped with a smooth and creamy brown butter frosting that makes every bite irresistible. Combining the comforting taste of homemade banana bread with the tender texture of cake-like brownies, this easy dessert is perfect for using up ripe bananas and creating something special for family and friends.
Made with simple pantry ingredients, sour cream for extra moisture, and a homemade frosting with a delicious nutty aroma, these banana bread brownies are easy to prepare and wonderfully satisfying. The brown butter frosting adds a rich, caramel-like flavor that complements the sweetness of the bananas beautifully.
Whether you serve them as an afternoon treat, bring them to a potluck, or prepare them for a weekend dessert, these banana bread brownies are a delicious way to turn everyday ingredients into something memorable.
Why You’ll Love These Banana Bread Brownies
- Soft and moist texture: Ripe bananas and sour cream help create tender, flavorful squares.
- Rich brown butter frosting: Browning the butter adds a warm, nutty flavor that takes this dessert to the next level.
- Easy to make: Simple ingredients and straightforward steps make this recipe beginner-friendly.
- Perfect for ripe bananas: Use those spotty bananas sitting on your kitchen counter.
- Great for sharing: A 9-by-13-inch baking dish makes enough for a family gathering or dessert table.
- Make-ahead friendly: Bake the brownies in advance and frost them when you’re ready to serve.
Ingredients for Banana Bread Brownies
For the Banana Bread Brownies
- 3 ripe bananas, mashed: Very ripe bananas provide natural sweetness, moisture, and the signature banana flavor. Bananas with brown spots are ideal.
- 2 large eggs: Help bind the ingredients together and give the brownies structure.
- 1 cup sour cream: Adds moisture and tenderness while balancing the sweetness.
- 1 1/2 cups all-purpose flour: Provides the structure needed for soft, cake-like brownies.
- 1 cup granulated sugar: Sweetens the batter and complements the ripe bananas.
- 1 teaspoon baking soda: Helps the batter rise and creates a light texture.
- 1 teaspoon vanilla extract: Adds warmth and enhances the banana flavor.
- 1/4 teaspoon salt: Balances the sweetness and brings out the other flavors.
For the Brown Butter Frosting
- 1/2 cup unsalted butter: The star of the frosting. Browning it creates a rich, nutty aroma and a deeper flavor.
- 2 cups powdered sugar: Gives the frosting its sweetness and smooth consistency.
- 3 tablespoons milk: Helps create a creamy, spreadable frosting.
- 1 teaspoon vanilla extract: Adds a pleasant vanilla aroma.
- 1/4 teaspoon ground cinnamon, optional: Adds gentle warmth that pairs beautifully with bananas and brown butter.
How to Make Banana Bread Brownies
Step 1: Prepare the Baking Dish
Preheat your oven to 350°F (175°C).
Lightly grease a 9-by-13-inch baking dish with butter or nonstick cooking spray. If desired, line the dish with parchment paper, leaving some overhang on the sides to make removing the brownies easier.
Set the prepared pan aside while you make the batter.
Step 2: Mash the Bananas
Peel the ripe bananas and place them in a large mixing bowl.
Using a fork, mash them until mostly smooth, leaving a few small lumps for texture. The riper the bananas, the easier they will be to mash and the more pronounced their flavor will be.
Step 3: Add the Wet Ingredients
Add the eggs to the mashed bananas and whisk until thoroughly combined.
Stir in the sour cream and vanilla extract until the mixture is smooth and creamy.
Add the granulated sugar and mix until it is evenly incorporated.
Step 4: Combine the Dry Ingredients
In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
Mixing the dry ingredients separately helps distribute the baking soda and salt evenly throughout the flour, promoting consistent baking.
Step 5: Make the Batter
Gradually add the dry ingredients to the banana mixture.
Use a spatula or wooden spoon to stir gently until the flour disappears and a thick, smooth batter forms.
Avoid overmixing. Excessive stirring can develop the gluten in the flour and make the finished brownies less tender.
Step 6: Fill the Baking Dish
Pour the banana batter into the prepared baking dish.
Use a spatula to spread the batter evenly into the corners and smooth the surface. An even layer helps the brownies bake at a consistent rate.
Step 7: Bake the Banana Bread Brownies
Place the dish in the preheated oven and bake for 25 to 30 minutes.
The top should become lightly golden, and the center should be set. Insert a toothpick into the middle of the brownies. It should come out clean or with a few moist crumbs, but no wet batter.
If the center still appears wet, continue baking for a few additional minutes and check again.
Step 8: Cool the Brownies Slightly
Remove the baking dish from the oven and place it on a wire rack.
Allow the brownies to cool while you prepare the brown butter frosting. They should be slightly warm rather than piping hot when you spread the frosting over them.
Step 9: Brown the Butter
Place the unsalted butter in a small, light-colored saucepan over medium heat.
Allow it to melt, stirring occasionally. The butter will begin to foam and bubble as its water evaporates. Continue cooking, watching carefully as golden-brown bits develop at the bottom of the pan.
When the butter smells nutty and the milk solids turn golden brown, immediately remove the saucepan from the heat.
Brown butter can burn quickly, so do not leave it unattended. Transfer it to a heat-safe mixing bowl if necessary to stop the cooking process.
Allow the browned butter to cool for about 5 minutes.
Step 10: Make the Frosting
Gradually add the powdered sugar to the browned butter, whisking as you go.
Add the milk and vanilla extract, then whisk until the frosting becomes smooth, creamy, and spreadable.
If you prefer a little extra warmth, stir in the optional ground cinnamon.
If the frosting is too thick, add more milk one teaspoon at a time. If it becomes too thin, add a little more powdered sugar until it reaches the desired consistency.
Step 11: Frost the Brownies
Spread the brown butter frosting generously over the slightly warm banana bread brownies.
Use a spatula to create gentle swirls across the surface. The warmth of the brownies will help the frosting spread smoothly, while the nutty brown butter aroma complements the banana flavor.
Avoid frosting the brownies while they are extremely hot, as this can cause the frosting to melt excessively.
Step 12: Cool, Slice, and Serve
Allow the frosted brownies to cool completely so the frosting can set.
Once cooled, cut them into squares using a sharp knife. For cleaner slices, wipe the knife between cuts.
Serve at room temperature for the softest texture and the fullest banana and brown butter flavor.
Tips for the Best Banana Bread Brownies
Use very ripe bananas. Bananas with plenty of brown spots are sweeter, softer, and easier to mash. They provide the strongest banana flavor.
Measure the flour correctly. Too much flour can make the brownies dry or dense. Spoon the flour into your measuring cup and level it off rather than packing it down.
Do not overmix the batter. Stir only until the dry ingredients are incorporated. A gentle mixing technique helps keep the brownies soft and tender.
Watch the butter carefully. Brown butter develops flavor quickly, but it can go from golden to burnt in moments. Remove it from the heat as soon as the milk solids turn golden brown and smell nutty.
Let the browned butter cool slightly. Very hot butter can make the frosting overly thin. A short cooling period helps it combine smoothly with the powdered sugar.
Adjust the frosting consistency gradually. Add milk a teaspoon at a time to avoid making the frosting too runny.
Frost while the brownies are slightly warm. A gently warm surface helps the frosting spread, but the brownies should not be hot enough to melt it completely.
Allow enough cooling time. Waiting until the frosting sets makes the brownies easier to slice and serve neatly.
Easy Variations
Banana Bread Brownies with Walnuts
Fold 1/2 cup of chopped walnuts or pecans into the batter before baking. The nuts add a pleasant crunch and pair naturally with the bananas and brown butter.
Chocolate Chip Banana Brownies
Add 1/2 cup of semisweet or dark chocolate chips to the batter for a chocolatey twist. The chocolate melts into the soft banana base and creates pockets of rich flavor.
Cinnamon Banana Bread Brownies
Add 1/2 teaspoon of ground cinnamon to the dry ingredients. This gives the brownies a warm, comforting flavor that works especially well with the brown butter frosting.
Cream Cheese Frosting
If you prefer a tangy topping, replace the brown butter frosting with cream cheese frosting. Beat softened cream cheese with butter, powdered sugar, and vanilla until smooth and creamy.
Maple Brown Butter Frosting
Replace 1 tablespoon of the milk with pure maple syrup. The maple flavor complements the nutty butter and ripe bananas beautifully. Add the syrup gradually and adjust the powdered sugar if needed.
Brown Sugar Banana Brownies
Replace part of the granulated sugar with light brown sugar for a deeper, molasses-like sweetness. The finished brownies will have a slightly richer flavor.
Gluten-Free Banana Bread Brownies
Use a suitable gluten-free all-purpose flour blend designed for baking. Choose a blend that includes a binder such as xanthan gum, if needed, and check the brownies for doneness because baking times may vary.
What to Serve with Banana Bread Brownies
These banana bread brownies are delicious on their own, but they also pair well with a variety of drinks and accompaniments.
- Coffee: The slightly bitter flavor of coffee balances the sweetness of the frosting.
- Hot tea: Black tea or chai complements the banana and cinnamon notes.
- Cold milk: A classic pairing for a soft, sweet dessert.
- Vanilla ice cream: Adds a cool, creamy contrast to the brown butter frosting.
- Fresh berries: Strawberries or raspberries provide a bright, fruity balance.
- Whipped cream: A small dollop creates a light finishing touch.
- Caramel sauce: A light drizzle adds another layer of sweetness for special occasions.
For a simple dessert plate, serve a square of banana bread brownie with a cup of coffee or a small scoop of vanilla ice cream.
How to Store Banana Bread Brownies
Proper storage helps keep these brownies moist and the frosting delicious.
At room temperature: If the brownies are made with shelf-stable ingredients and the frosting contains no perishable additions, they can generally be kept in an airtight container in a cool environment for up to 2 days. Refrigeration is the safer choice for longer storage, especially in a warm kitchen.
In the refrigerator: Store the brownies in an airtight container for up to 5 days. Separate layers with parchment paper if stacking them.
In the freezer: For the best quality, freeze the brownies without frosting when possible. Wrap individual portions tightly and place them in a freezer-safe container for up to 3 months. Thaw in the refrigerator, then prepare and spread fresh frosting.
Frosted brownies can also be frozen, although the frosting texture may change slightly after thawing.
Can You Make Banana Bread Brownies Ahead of Time?
Yes. These brownies are a great make-ahead dessert for gatherings, celebrations, and busy weeks.
Bake the banana brownies a day in advance and allow them to cool completely. Store them covered, then prepare the brown butter frosting and spread it over the brownies before serving.
You can also frost the brownies ahead of time and refrigerate them in an airtight container. Allow them to sit at room temperature for about 20 to 30 minutes before serving for a softer texture.
Frequently Asked Questions
Are banana bread brownies the same as regular brownies?
No. Traditional brownies are usually chocolate-based and have a dense, fudgy texture. Banana bread brownies are made with mashed bananas and have a soft, moist, cake-like texture that resembles banana bread cut into bars.
Why are my banana bread brownies too dense?
Overmixing the batter, using too much flour, or adding too much banana can affect the texture. Measure the ingredients carefully and stir only until the flour is incorporated.
Can I use frozen bananas?
Yes. Thaw frozen bananas completely and drain away any excess liquid before mashing them. Frozen bananas can be softer and wetter than fresh ripe bananas, so removing excess moisture helps keep the batter at the right consistency.
How do I know when the brownies are done?
The top should be lightly golden, and the center should be set. Insert a toothpick into the middle. It should come out clean or with a few moist crumbs, without wet batter.
Why did my brown butter frosting turn out too thin?
The butter may have been too hot, or too much milk may have been added. Allow the browned butter to cool slightly before mixing in the powdered sugar. If the frosting is too thin, gradually add more powdered sugar until it becomes spreadable.
Can I make the frosting without browning the butter?
Yes. You can use softened or melted unsalted butter for a simpler buttercream-style frosting. However, browning the butter creates the distinctive nutty flavor that makes this recipe special.
Can I reduce the sugar?
You can reduce the granulated sugar slightly, but this may change the sweetness and texture. The powdered sugar in the frosting is also important for creating its consistency, so reduce it cautiously and adjust the liquid as needed.
Can I make these brownies without sour cream?
Plain full-fat Greek yogurt can be used as a substitute for sour cream in a similar quantity. It provides moisture and a slight tang, although the texture may vary slightly.
Do these brownies need to be refrigerated?
Refrigeration is recommended for longer storage, particularly when the frosting contains milk. Store the brownies in an airtight container and allow them to soften slightly at room temperature before serving.
Banana Bread Brownies with Brown Butter Frosting Recipe Card
Prep Time: 15 minutes
Bake Time: 25–30 minutes
Frosting Time: 10 minutes
Cooling Time: 30 minutes
Total Time: Approximately 1 hour 20 minutes to 1 hour 25 minutes
Servings: 12–16 brownies
Course: Dessert
Cuisine: American
Ingredients
For the Banana Bread Brownies
- 3 ripe bananas, mashed
- 2 large eggs
- 1 cup sour cream
- 1 1/2 cups all-purpose flour
- 1 cup granulated sugar
- 1 teaspoon baking soda
- 1 teaspoon vanilla extract
- 1/4 teaspoon salt
For the Brown Butter Frosting
- 1/2 cup unsalted butter
- 2 cups powdered sugar
- 3 tablespoons milk
- 1 teaspoon vanilla extract
- 1/4 teaspoon ground cinnamon, optional
Instructions
- Preheat the oven to 350°F (175°C). Grease a 9-by-13-inch baking dish or line it with parchment paper.
- Mash the ripe bananas in a large bowl until mostly smooth.
- Whisk in the eggs, then stir in the sour cream and vanilla extract. Add the granulated sugar and mix until combined.
- In a separate bowl, whisk together the flour, baking soda, and salt.
- Gradually stir the dry ingredients into the banana mixture until just combined. Do not overmix.
- Pour the batter into the prepared baking dish and spread it evenly.
- Bake for 25 to 30 minutes, or until the top is lightly golden and a toothpick inserted into the center comes out clean or with a few moist crumbs.
- Remove from the oven and let the brownies cool slightly.
- To make the frosting, melt the butter in a saucepan over medium heat. Continue cooking, stirring occasionally, until golden-brown bits form and the butter smells nutty.
- Remove the butter from the heat and cool for about 5 minutes.
- Whisk in the powdered sugar, milk, and vanilla until smooth. Add the optional cinnamon. Adjust the consistency with a little extra milk or powdered sugar if necessary.
- Spread the frosting over the slightly warm brownies.
- Allow the brownies to cool completely and the frosting to set before slicing.
- Cut into 12 to 16 squares and serve at room temperature.
Recipe Notes
- Use very ripe bananas for the best flavor and moisture.
- Measure the flour carefully to avoid a dense texture.
- Stir the batter gently and avoid overmixing.
- Watch the butter closely while browning to prevent burning.
- Add milk to the frosting gradually until it reaches a spreadable consistency.
- Store leftovers in an airtight container in the refrigerator for up to 5 days.
Final Thoughts
These Banana Bread Brownies with Brown Butter Frosting bring together everything you love about homemade banana bread in an easy-to-serve dessert bar. The soft banana base is moist and tender, while the rich brown butter frosting adds a nutty sweetness that makes each square feel extra special.
Whether you are using up ripe bananas, preparing a treat for guests, or looking for a new family favorite, this simple recipe is a wonderful choice. Bake a pan, spread on the creamy frosting, and enjoy a comforting homemade dessert with every bite.