Soft Banana Bread Cake Bars with Rich Brown Butter Frosting
If you’ve been holding onto a couple of old bananas waiting for the perfect time to use them, these Banana Bread Cake Bars are the best green light you can get!
What Makes This Such a Great Recipe
Anytime I’ve got a couple of brown bananas sittin’ on the counter, my mind goes straight to baking. Banana bread is always a good idea, but sometimes I want something a little more shareable, a little more dessert-like, you know what I mean?
They bake up in a simple 9×9 pan, slice cleanly into smaller bars, and feel just right for everything from potlucks to Sunday supper desserts. The texture lands somewhere between banana cake and classic banana bread, with a moist crumb that stays tender for days thanks to sour cream in the batter.
If you’ve ever made banana bread in a loaf pan and thought, “This is good, but it could be better,” this is your next recipe! And after that, give this Buttery Apple Crackle Cake a go!
Ingredients You’ll Need
- Mashed ripe bananas
- Granulated sugar
- Unsalted butter, melted
- Large eggs
- Vanilla extract
- Sour cream (or Greek yogurt)
- Baking soda
- Baking powder
- Salt
- All-purpose flour
- Powdered sugar
- Heavy cream
Tips for the Best Banana Bread Bars
- Use room temperature ingredients when you can. Sour cream and eggs blend more smoothly and help create a soft, even batter.
- Don’t overmix once the flour goes in. Stir just until combined for the best moist crumb.
- Line your baking pan with parchment paper. It makes lifting and slicing the bars so much easier, especially if you want clean edges.
- Let the bars cool completely before frosting. Warm bars will melt the frosting right off the top.
- If your bananas aren’t quite ready, toss them in a paper bag overnight or bake them (peel on) at 300°F for about 15 minutes until softened.
How to Make Banana Bread Cake Bars
Step 1: Prep the Pan
Preheat your oven to 350°F and line a 9×9-inch baking pan with parchment paper or lightly grease it.
Step 2: Mix the Wet Ingredients
In a large mixing bowl, whisk together mashed bananas, granulated sugar, melted butter, eggs, and vanilla extract until smooth. Stir in the sour cream.
Step 3: Add the Dry Ingredients
Sprinkle baking soda, baking powder, and salt over the wet mixture, then gently stir. Add the flour and fold just until combined. The batter should be smooth but not overworked.
Step 4: Bake
Spread the batter evenly in the prepared pan. Bake for 25–32 minutes, until the center is set and a toothpick comes out clean. Let cool for at least 30 minutes.
Step 5: Making the Brown Butter Frosting
Add butter to a small saucepan over medium heat. Let it melt, foam, and turn golden brown, about 4–6 minutes. Remove from heat and cool slightly.
In a bowl, whisk powdered sugar, vanilla, and salt. Pour in the browned butter and 1 tablespoon of heavy cream. Mix slowly, adding more cream as needed.
Spread over the cooled bars, slice, and you’re ready to dig in!
Storage Tips
Store banana bread cake bars in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days. They freeze beautifully, too; just wrap them tightly and freeze for up to 2 months. Thaw overnight before serving.
Frequently Asked Questions
Yes! Full-fat Greek yogurt works just as well and keeps the bars moist.
Brown butter adds a deep, nutty flavor that plain melted butter just can’t match. It’s worth the extra few minutes.
You can, but the bake time will be longer, and the bars will be thicker. This recipe really shines in a square pan.
Ingredients
For the Banana Bread Cake Bars
- 3/4 cup mashed ripe bananas about 1–2 bananas
- 3/4 cup granulated sugar
- 1/3 cup unsalted butter melted
- 2 large eggs
- 1 teaspoon vanilla extract
- 1/2 cup sour cream or Greek yogurt
- 3/4 teaspoon baking soda
- 1/4 teaspoon baking powder
- 1/2 teaspoon salt
- 1 1/2 cups all-purpose flour
For the Brown Butter Frosting
- 6 tablespoons unsalted butter
- 1 1/2 cups powdered sugar
- 1 –2 tablespoons heavy cream
- 1 teaspoon vanilla extract
- Pinch of salt
Instructions
Banana Bread Cake Bars
- Preheat the oven to 350°F (175°C). Line a 9×9-inch baking pan with parchment paper or lightly grease it.
- Whisk together the mashed bananas, sugar, melted butter, eggs, and vanilla until smooth.
- Stir in the sour cream. Sprinkle the baking soda, baking powder, and salt over the mixture and gently mix.
- Add the flour and fold just until the batter is combined and smooth. Spread the batter evenly in the prepared pan and bake for 25–32 minutes, or until the center is set and a toothpick inserted into the middle comes out clean.
- Let the bars cool in the pan for at least 30 minutes before frosting.
Brown Butter Frosting
- Add the butter to a small saucepan over medium heat and cook for 4–6 minutes, until the butter melts, foams, and turns golden brown. Remove from heat and let cool for 5–10 minutes.
- In a bowl, whisk together the powdered sugar, vanilla, and salt. Pour in the browned butter and 1 tablespoon of heavy cream.
- Mix with a hand mixer until smooth and creamy, adding additional heavy cream as needed to reach a spreadable consistency. Spread the frosting over the fully cooled bars, slice, and serve.