Easy Cake Mix Banana Bars with Cream Cheese Frosting

These cake mix banana bars are moist banana cake on the bottom with a rich cream cheese frosting on the top and are so quick and easy to make.

Wide image of banana bar sliced with cream cheese icing on a white plate.

The secret to this recipe is that you’ll use a cake mix as the base. That means the banana bars will always turn out moist and delicious, but by adding in a few other ingredients, you won’t get that cake mix box taste. It’ll taste like it’s homemade and made from scratch.

Hey there! Before you scroll, there are lots of helpful things in this post…including an FAQ section, which may answer any questions you might have about this recipe. Enjoy!

Table of Contents:

These frosted banana bars are a great way to use up those overripe bananas that you’ve got lying around and these will come together in no time at all, so you won’t spend a ton of time in the kitchen.

Not only are these banana bars incredibly simple to make, but they’re also super versatile. You can add walnuts, pecans, chocolate chips, white chocolate chips, or other mix-ins for a more customized dessert.

These bars can be eaten on a plate with a fork, or just cut into squares and eat them like a hand-held treat. They’re great when you need a quick dessert or snack that everyone will love.

Pinterest image with large slice of banana cake on a white plate.

Ingredient Notes:

Now let’s talk about some of the ingredients in these banana cake bars. (The printable list of all ingredients are in the recipe card below.)

Ingredients for the cake bars:

Very ripe bananas: You’ll need three bananas and it’s good to use very ripe bananas because they have the most flavor.

Yellow cake mix: This is what makes these cake bars so quick and easy to make. You’ll add other ingredients to the cake mix so that it tastes completely homemade.

Cinnamon: Don’t skip the cinnamon. It goes perfectly with the bananas and adds a hint of flavor to give it that banana bread taste.

Eggs, butter and oil: Eggs will provide structure and moisture and the butter and oil will also give flavor and moisture.

Sour cream: This just makes baked goods so tasty and moist and gives them a wonderful texture.

Milk and vanilla extract: Milk will provide needed moisture and vanilla extract enhances the flavor of everything.

Optional nuts: Feel free to add nuts if you like them and if you’re not allergic.

Ingredients for the cream cheese icing:

Butter and cream cheese: Butter will add great flavor to this frosting and cream cheese gives a little tang and goes perfectly with the flavor of the bananas.

Confectioner’s sugar: This is needed to thicken up the frosting and add sweetness.

(Make sure to check out the FAQ section below in this post for ingredient and substitution questions.)

Close up image of banana cake with icing on a white plate and a fork.

How to make these cake bars:

Let’s talk about how to make banana cake bars: (The printable instructions are in the recipe card below.)

Step 1:

First, you want to make the cake bars. To do that, preheat the oven to 350 degrees F and spray a 13×9 inch baking dish with nonstick spray, then set it aside.

Sprayed baking dish on a white and pink background.

Step 2:

Mash up the bananas in a mixing bowl. Then melt the butter, but make sure it’s cooled down a bit.

Also make sure that the eggs, sour cream and milk are no longer cold. If they’re cold, the batter can clump up when mixed.

Banana cake batter poured into a baking dish.

Step 3:

Next, add all of the cake bar ingredients, except for the nuts, to a large mixing bowl and mix with an electric mixer on medium until well mixed.

At this point, you can add in nuts if you want or chocolate chips if desired.

Banana cake batter poured into a baking dish.

Step 4:

Next, pour the batter into the prepared baking dish and bake the bars at 350 degrees F for approximately 30-35 minutes.

Step 5:

After baking, remove the baked cake bars from the oven and set on a cooling rack to cool completely before adding the frosting.

Baked banana bars in a baking dish.

Step 6:

Now, you’ll make the frosting. To do that In a large bowl, add the room-temperature butter and mix well.

Step 7:

Next, add the room-temperature cream cheese and mix well again.

Step 8:

Now, add the salt, vanilla, confectioners sugar and milk and mix well until it’s all smooth.

Cream cheese buttercream mixed in a large white mixing bowl.

Step 9:

Once the cake bars are cooled, add the cream cheese frosting.

Iced banana bars with two cups of coffee.

Step 10:

Enjoy these banana bars either cold or at room temperature, but store covered well in the refrigerator.

Large slice of banana bars with icing with a fork cutting a piece off.

(Remember that the instructions will also be in the recipe card below.)

Wide image of banana bar sliced with cream cheese icing on a white plate.

Easy Cake Mix Banana Bars with Cream Cheese Frosting

These cake mix banana bars are moist banana cake on the bottom with a rich cream cheese frosting on the top and are so quick and easy to make.
5 from 2 votes
Print Pin Save Rate
Course: Dessert
Cuisine: American
Keyword: cake mix banana bars with cream cheese frosting
Prep Time: 15 minutes
Cook Time: 30 minutes
Total Time: 45 minutes
Servings: 15 slices
Calories: 314kcal
Author: Kara @ Quick and Easy Baking

Ingredients

For the cake:

  • 3 medium-sized very ripe bananas, mashed
  • 1 (14 ounce) box yellow cake mix
  • 1 1/2 teaspoon cinnamon
  • 3 large eggs, near room temperature
  • 1/4 cup unsalted butter, melted and cooled down a bit
  • 1/4 cup vegetable oil
  • 1/2 cup sour cream, near room temperature
  • 1/2 cup milk, near room temperature
  • 1 teaspoon vanilla extract
  • 1 cup chopped walnuts or pecans (optional)

For the frosting:

  • ½ cup unsalted butter, room temperature (1 stick)
  • 1 (8 ounce package) cream cheese, near room temperature
  • 1 pinch salt
  • 1 teaspoon vanilla extract
  • 3 cups confectioner's sugar
  • 1 teaspoon milk (may use more if needed to reach desired consistency)
Have questions?Make sure to check out the Tips & FAQ section in the post!

Instructions

For the cake:

  • Preheat the oven to 350 degrees F. Spray a 13×9 inch baking dish with nonstick spray and set aside.
  • Make sure the bananas are mashed well, that the butter has cooled down a bit and that the eggs, sour cream and milk are no longer cold. If they are cold, then it could clump the melted butter when mixed, which could cause the ingredients not to mix well and make holes when the batter is baked.
  • In a large mixing bowl, add all of the cake bar ingredients, except for the nuts and mix with an electric mixer on medium until well mixed.
  • Add the nuts, if desired, and mix in by hand.
  • Pour the batter into the prepared baking dish and bake at 350 degrees F for approximately 30-35 minutes. A toothpick inserted into the center of the cake bars should come out with a few moist crumbs on it, or clean, but no raw batter. Be careful not to over-bake as that will make the cake bars dry.
  • Remove the baked cake bars from the oven and set on a cooling rack to cool completely before adding the frosting.

For the frosting:

  • In a large bowl, add the room-temperature butter and mix well with an electric mixer on medium to medium-high speed until smooth.
  • Add the room-temperature cream cheese and mix well on medium-high speed until smooth.
  • Add the salt, vanilla, confectioners sugar and milk and mix on medium-high speed until smooth.
  • Check the consistency. If it’s too thick, add another teaspoon of milk, mix and repeat until the desired consistency is reached.
  • Add to cooled cake bars.
  • See the notes section for best ways to store these, serve them and for more questions.

Notes

How to Store: Since the frosting on these cake bars is made with cream cheese, these bars should be covered and stored in the refrigerator and can last up to 5-6 days.
How to serve: These cake bars can be served/eaten either chilled, at room temperature, or warmed.
For other questions: Make sure to check out the TIPS & FAQs for this recipe in the blog post, which should answer other questions you may have about ingredients, substitutions, other pan sizes etc.
Nutritional values are an estimate.
*This recipe card may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Nutrition

Calories: 314kcal | Carbohydrates: 32g | Protein: 3g | Fat: 21g | Saturated Fat: 8g | Polyunsaturated Fat: 6g | Monounsaturated Fat: 5g | Trans Fat: 0.4g | Cholesterol: 63mg | Sodium: 24mg | Potassium: 158mg | Fiber: 1g | Sugar: 27g | Vitamin A: 411IU | Vitamin C: 2mg | Calcium: 37mg | Iron: 0.5mg
Baking at higher elevation?You’ll need to make adjustments for high elevations. This website does not specialize in that type of baking. Please take time to research high elevation baking websites for adjustments that should be made.
DislaimersTo see food safety, allergy & nutrition disclaimers, go here: Disclaimers!

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Tips & FAQs:

Tip for the bananas:

Try to use very ripe bananas as those have the most flavor to them.

What brand of cake mix should I use?

I used Betty Crocker, but you could probably use any major brand’s cake mix.

Do I have to use the cinnamon?

Well, you don’t have to, but it does add good flavor and it may not taste as good if you don’t.

Why do some of the liquid ingredients need to be near room temperature?

This is because the liquid ingredients need to be mixed with the melted butter and all those ingredients need to be around the same temperature or everything can clump up and could cause texture issues in the cake bars.

I don’t have sour cream, what can I use instead?

You can try using unflavored full-fat yogurt.

I don’t have unsalted butter, can I use salted?

You can use salted butter for both the cake bars and the frosting, but you will need to omit the additional salt that those recipes call for so that too much salt isn’t inadvertently added.

Do I have to add nuts?

No, not at all. Adding nuts is purely optional.

How can I tell when these cake bars are done baking?

These are done baking when a toothpick inserted into the center comes out with a few moist crumbs on it or clean, but no raw batter.

Can these banana bars be frozen?

These can be made ahead of time and frozen (without the frosting) if desired. Let the baked cake bars cool completely. If baked in a disposable 13×9 inch pan, you can wrap the entire pan with plastic wrap and foil, then freeze, or you can just cut the bars up and place them in a freezer bag and freeze up to 2 months.

To thaw, place the wrapped cake on the counter at room temperature and let thaw completely, then remove the wrapping, or pull the frozen squares out of the freezer bag and place into an airtight container. Once defrosted, add the frosting.

How do I store these and how long do they last?

Since the frosting on these cake bars is made with cream cheese, these bars should be covered and stored in the refrigerator and can last up to 5-6 days.

Can this recipe be made in a loaf pan?

Yes, probably although I haven’t tested that out. You might need to bake for a little longer though if using a loaf pan as the batter will be deeper in the pan.

Can this recipe be made into cupcakes or muffins?

You should be able to bake this batter in cupcake pans with cupcake liners although I have not officially tried that. The recipe will probably make better muffins than it will cupcakes as the recipe is specifically for a cake bar texture, which is a little denser than cupcake batter would be.
Basically, the texture would be closer to a muffin texture than a cupcake texture.
If you do bake this batter as muffins/cupcakes, bake at the same temperature, but start checking for doneness at around 18 minutes or so as they will bake faster in cupcake pans than a 13×9 inch pan.

What can I add to the batter?

Feel free to add nuts, chocolate chips, white chocolate chips, peanut butter chips or whatever you like.

How should I store these cake bars?

These cake bars should be stored in an airtight container or covered in plastic wrap in the refrigerator and can last up to 5-6 days.

What’s the best way to serve/eat these?

These cake bars can be served/eaten either chilled, at room temperature, or warmed.

Top view of slice of banana bars with icing on a white plate.

Video:

Supplies used for this recipe:

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases. 

Collage image with two images of banana bars with cream cheese buttercream and text overlays.
Kara

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