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brown butter banana bread bars in a pan

Brown Butter Frosted Banana Bread Bars

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5 from 49 reviews

  • Author: Jenna Barnard
  • Total Time: 1 hour 15 minutes
  • Yield: 24 bars


These banana bread bars are the perfect way to use up those spotty ripe bananas sitting on your counter! They’re also made extra special with brown butter both in the batter and in the sweet frosting on top.


Banana Bread Bars

  • 1/2 cup (110g) unsalted butter
  • 1 cup (200g) granulated sugar
  • 1/2 cup (105g) light brown sugar, packed
  • 2 large eggs
  • 1 cup (250g) sour cream
  • 1 1/2 cups (385g) ripe banana, mashed (4-ish bananas)
  • 1 tsp vanilla extract
  • 1 tsp baking soda
  • 1/2 tsp kosher salt
  • 2 cups (265g) all purpose flour

Brown Butter Frosting

  • 3/4 cup (170g) unsalted butter (+ 2 tbsp chilled)
  • 3 cups (300g) powdered sugar
  • 1 tsp vanilla extract
  • 1/4 cup (60g) milk, room temp


Banana Bread Bars

  1. Preheat the oven to 350F and grease an 11×15 jelly roll pan.
  2. Combining the butter from the banana bread bars and the butter for the frosting (minus the additional 2 tbsp) equates to 1 1/4 cup of butter. Add this butter to a saucepan over medium heat to brown.
  3. It will go from melted, to loud and bubbly, to quiet and foamy. Keep stirring until it turns a light amber color.
  4. Dividing the browned butter, measure out 1/2 cup for the banana bread bars and pour the remaining brown butter in a mixing bowl. Now drop in the extra 2 tablespoons of butter into the mixing bowl and mix to melt.
  5. Place the bowl of brown butter into the refrigerator as it needs to solidify for the frosting.
  6. Now pour the 1/2 cup of brown butter (reserved for the bars) into a seperate mixing bowl and whisk in the sugar and brown sugar.
  7. Then whisk in the eggs, followed by the sour cream, banana, and vanilla.
  8. Whisk in the baking soda and salt, followed by the flour.
  9. Pour the batter into the prepped pan and spread even.
  10. Bake for 25-30 minutes.
  11. While the bars cool, make the frosting.

Brown Butter Frosting

  1. By now, the refrigerated bowl of brown butter should be solid but still soft.
  2. Using a hand or stand mixer with the whisk attachment, gradually mix in the powdered sugar one cup at a time, followed by the vanilla and milk.
  3. Spread the frosting over the slightly warm bars and allow them to cool at room temp for about 30 minutes. Then slice and enjoy!
  • Prep Time: 20 minutes
  • Cooling Time: 30 minutes
  • Cook Time: 25 minutes
  • Category: Dessert
  • Method: Baking
  • Cuisine: American
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