Banana Bread Brownies

These banana bread brownies taste like the best parts of banana bread and a soft, cake-like blondie all in one pan. They’re extra moist from sour cream and ripe bananas, with a little crunch from chopped walnuts. A warm, nutty brown butter frosting gets poured over the bars so it soaks in and sets into a rich, sweet layer. They’re perfect for potlucks, holidays, or anytime you’ve got a few overripe bananas waiting on the counter. Cut them small for a crowd, or into big bakery-style squares for a cozy dessert.

Ingredients

For the Banana Bread Brownies:

• 1-1/2 cups sugar
• 1 cup sour cream
• 1/2 cup butter
• 2 eggs
• 4 ripe bananas, mashed
• 2 tsp vanilla extract
• 2 cups all-purpose flour
• 1 tsp baking soda
• 3/4 tsp salt
• 1/2 cup chopped walnuts

For the Brown Butter Frosting:

• 1/2 cup butter
• 4 cups powdered sugar
• 1 1/2 tsp vanilla extract
• 3 Tbsp milk

Directions

1. I start by heating my oven to 375°F. I grease and flour a 15×10-inch jelly roll pan.
2. For the brownies, in a large bowl, I beat together the sugar, sour cream, butter, and eggs until creamy. I blend in the mashed bananas and vanilla extract.
3. I then add the flour, baking soda, and salt to the bowl and blend everything for about 1 minute. I stir in the chopped walnuts last.
4. I spread the batter evenly into the prepared pan and bake it for 20 to 25 minutes, or until it turns golden brown.
5. Meanwhile, for the frosting, I heat 1/2 cup of butter in a large saucepan over medium heat until it starts boiling. I let the butter turn a delicate brown and then remove it from the heat immediately.
6. I add the powdered sugar, vanilla extract, and milk to the browned butter. I whisk it all together until smooth; the consistency should be thicker than a glaze but thinner than frosting.
7. Using a spatula, I spread the brown butter frosting over the warm bars. It’s easier to spread the frosting while the bars are still warm.

Prep Time: 20 minutes | Cooking Time: 25 minutes | Total Time: 45 minutes
Kcal: 290 kcal | Servings: 24

Tips

For extra flavor and texture, lightly toast the walnuts in a dry skillet or in the oven for a few minutes before stirring them into the batter; this makes them crunchier and brings out their nutty taste.

Let the frosted bars cool completely in the pan before cutting so the brown butter topping can fully set—then store leftovers tightly covered at room temperature for up to 3 days or in the fridge for slightly firmer bars.