You know that feeling when you make a GF treat and everyone asks for the recipe, gluten-free or not? Be prepared when you serve up the world’s best frosted banana bars made with all purpose gluten-free flour. These homemade snack bars a legendary mash up of banana bread and banana sheet cake, slathered in a gooey brown butter frosting and ready in only 30 minutes!

a stack of two banana bars with a sliced banana piece on top.
Love banana bread and sheet cake? This is your gluten-free dessert magic! It doesn’t get any better, or more simple, to whip up a batch of banana bars.

Want to Save This Recipe?

Enter your email below & we'll send it straight to your inbox. Plus you’ll get affordable and easy gluten-free recipes delivered each week!

Browned Butter Frosted Gluten-Free Banana Bars

What doesn’t sound more appealing then a banana bread snack cake? The words “snack” suggests it’s sustenance you need, while who doesn’t love an excuse for cake?! If you have some ripe bananas laying around, grab a mixing bowl and whip up a batch of homemade gluten-free banana bars.

Baking with bananas and gluten-free flour adds an extra boost of moistness GF desserts and breads need without any fancy tricks. When making my famously fluffy gluten-free banana muffins, I’ve found resting the batter before baking coats the GF starches to build out the structure.

Since banana bread bars have a higher amount of sugar and they are baked in a thinner sheet cake layer, no resting is necessary. You are left with a fluffy, moist and gooey frosted banana slab cake no one will be the wiser is actually gluten-free.

As if that isn’t good enough, this is something I considered to be “emergency dessert” in my homemade gluten-free cake recipe collection. From start to finish you can be diving into warm slabs of banana bread cake in little as 30 minutes. You don’t even have to wait for the bars to cool before frosting because it’s best spread on warm right out of the oven, similar to fudgy gluten-free Texas sheet cake.

And just like sheet cake, you have the option to mix in chopped nuts, chocolate chips, or keep it simple with a classic, old fashioned banana bar taste.

Let’s Make This Together!

(Below shows step-by-step photos and modified instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.)

Easy one bowl batter

This easy banana bar batter comes together in minutes. First cream together the softened butter with both sugars until light and fluffy, about 3 minutes. Once that’s combined add in the eggs, mashed bananas, and extract.

When I make gluten-free banana recipes I always include the exact amount of mashed bananas because GF flour has a hard time soaking up extra moisture. Baking recipes need the exact volume or grams listed because a banana’s size can vary drastically!

mixing bowl with creamed butter eggs and mashed bananas.

Mix in dry ingredients and bake

To the mixture add the gluten-free flour, baking soda, and salt. Typically I recommend using Cup4Cup gluten-free flour for baked goods, but these bars are pretty adaptable. Any preferred gluten-free flour blend works well.

Pour into a greased jelly roll pan, which is about 10X15-inches. This is smaller then a traditional sheet pan, which would create too thin of a layer.

Since this is a thinner cake, it only needs about 20 minutes to bake in a 350℉ oven. During the last few minutes of baking, start to make the frosting.

gluten free flour being mixed into the bowl.

Epically good browned butter frosting

Don’t be intimidated by making browned butter. Even though it sounds fancy schmancy, I walk you through it.

In a large enough saucepan to add the other frosting ingredients, melt the butter. First it will foam and then white milk solids will settle to the bottom of the pan. Once the milk solids go from white to golden brown, immediately pull it from the heat.

Whisk in 1 cup powdered sugar, milk, and salt until smooth, then slowly add in the remaining powdered sugar until the frosting is thick yet spreadable.

Once the bars come out of the oven, spread that glorious frosting all over and dig in!

a small saucepan with melted browned butter.
a spoon holding up the frosting to show consistency.
a sliced bar on a white plate with a big bite taken out.
Bake a pure and simple version with gooey browned butter frosting or try one of the yummy mix-in ideas below!

Bonus Ideas to Boost the Goodness

GF banana bars don’t stick around long anyway you make them, but here are some other tasty additions to try out.

  • Mix chopped pecans or walnuts into the batter, or sprinkle on top of the frosting immediately. Press down lightly to stick.
  • Melt 1/4 cup creamy peanut butter in the microwave for 20 seconds. Drizzle on top of frosting and swirl together.
  • Make the brown butter frosting more of a glaze by halving all the frosting ingredients except leaving amount of milk the same.
  • For a touch of tang in frosting replace milk with buttermilk or substitute milk with 1/3 cup sour cream.
  • Add 1/2 cup miniature chocolate chips so they don’t sink down to the bottom of the pan. Then throw caution to the wind and sprinkle some on top of the warm frosting as well. 😎
an overhead shot of banana bread bar on a white and blue plate with a bite taken out
Serve these bars warm and gooey right out of the oven or store at room temperature until ready to dig in.

Save this recipe to your pinterest board!

Pin Now, Bake Later!

Let’s be friends on Pinterest! I’m always sharing great recipes!

Did you make this recipe? I love hearing from you! Leave a star rating and comment below the recipe card. It helps others when searching for recipes and I appreciate feedback from our community. You will always hear back from me! -Melissa

a stack of two banana bars with a sliced banana piece on top
4.23 stars (27 ratings)

Legendary Gluten-Free Banana Bars with Frosting

Melissa Erdelac of MamaGourmand headshot in patterned dress.Melissa Erdelac
Yield: 24 bars
Prep Time: 5 minutes
Cook Time: 20 minutes
Total Time: 25 minutes
You know that feeling when you make a GF treat and everyone asks for the recipe, gluten-free or not? Be prepared when you serve up the world's best frosted banana bars made with all purpose gluten-free flour. These homemade snack bars a legendary mash up of banana bread and banana sheet cake, slathered in a gooey brown butter frosting and ready in only 30 minutes!
Print Pin Rate Remove Ads

Ingredients
 

Banana Bars

Browned Butter Frosting

Equipment

Instructions
 

  • Preheat oven to 350°F. Grease a 15X10 jellyroll baking pan (see recipe notes for 9×13 pan).
  • In a large bowl, cream together the softened butter, sugar, and brown sugar until light and fluffy, about 3-5 minutes. Beat in the eggs, mashed bananas and vanilla until well combined.
    ½ cup unsalted butter, 1 cup granulated sugar, ½ cup packed brown sugar, 3 large eggs, 1 ½ cups mashed ripe bananas, 1 teaspoon vanilla extract
  • Add in flour, baking soda and salt. Mix well into the mixture.
    2 cups gluten free all-purpose flour, 1 teaspoon baking soda, ¼ teaspoon salt
  • Pour the batter into prepared baking pan and smooth evenly. Bake for 20-25 minutes, rotating pan halfway through baking. The bars are done when toothpick inserted in middle comes out clean. Meanwhile, start the frosting.

Brown Butter Frosting

  • As soon as bars come out of oven, or a little before, begin the frosting. In a medium saucepan melt the butter. Once the butter is fully melted watch carefully and stir occasionally so butter doesn't burn. First the butter will foam, then the milk solids will start to settle at the bottom. Watch for the milk solids to turn from white to golden brown. Once that happens, immediately remove from heat.
    ½ cup unsalted butter, 2 ½ cups powdered sugar, ¼ teaspoon salt, 3 tablespoons milk
  • Whisk in 1 cup powdered sugar, salt, and milk. Stir in the remaining powdered sugar. Add more milk if necessary for a thinner consistency. Immediately pour and gently spread on warm bars using an offset spatula. Cool slightly before slicing and serving.

Notes

Making in a 9X13-inch pan
If you prefer a thicker cake to frosting ratio, or don’t have a jellyroll pan on hand, this recipe can also be baked in a 9X13″ pan.
It will take longer to bake, so add 10 minutes to baking time. Be sure to insert a toothpick in the middle to check for it to be clean before taking them out of the oven.
Calories: 221kcal, Carbohydrates: 36g, Protein: 2g, Fat: 9g, Saturated Fat: 5g, Polyunsaturated Fat: 0.5g, Monounsaturated Fat: 2g, Trans Fat: 0.3g, Cholesterol: 41mg, Sodium: 105mg, Potassium: 70mg, Fiber: 1g, Sugar: 27g, Vitamin A: 278IU, Vitamin C: 1mg, Calcium: 19mg, Iron: 1mg
Did you make this recipe?Please leave a star rating and review below. It helps others when searching for recipes and I LOVE feedback!