Name: Banana Sheet Cake
Prep time: 30 min
Cook time: 30 min
Total time: 60 min
Ingredients: 2 cups mashed bananas (- from about 5-6 overripe bananas); 3/4 cup canola oil; 1 cup sour cream; 3 large eggs; 2 teaspoons vanilla extract; 1 1/4 cup brown sugar (- 225 grams); 1/2 cup granulated sugar (- 100 grams); 1 teaspoon baking soda; 1 teaspoon baking powder; 1 teaspoon kosher salt; 1 teaspoon cinnamon; 1/2 teaspoon nutmeg; 1/4 teaspoon ginger; 3 1/4 cups cake flour (- 422 grams); 1/2 cup unsalted butter; 1 cup brown sugar (- 200 grams); 1/3 cup milk (- plus a few more drops if needed to thin); 2 teaspoons vanilla extract; 2 cups powdered sugar (- 240 grams)

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Banana Sheet Cake combines a moist banana cake with a decadent caramel frosting. This cake makes a great dessert to take to potlucks or family gatherings, and is over-the-top delicious!

Try our family favorite Texas Sheet Cake Brownies next!

Side view of a small white plate in front of the sheet cake.

Frosted Banana Bread

There are SO many versions of banana bread and banana cakes on the internet. It can be confusing. Should I use oil or butter, how ripe should my bananas be, should I add chocolate chips or nuts, what kind of frosting should I use?

Regardless of the noise out there, I’m here to tell you that you should DEFINITELY make THIS banana cake SOON! Here are the reasons.

Why we love this recipe:

It’s super moist. Moist is what we all want in any cake, right? This banana sheet cake uses oil and lots of over-ripe bananas, as well as cake flour. It also has just the right proportion of dry to wet, resulting in just the right texture. MOIST! (Can I say that word too much here?)
This cake is delicious. I personally love using brown sugar in cakes and other baked goods. The molasses flavor really shines, and it pairs beautifully with the caramel frosting (uses brown sugar too). SO delish!
Leftovers are great for days. This is a large recipe, and leftovers taste great for several days! You can make it for your fam and pack it in lunches all week long. It’s also a perfect recipe for a gathering of any kind. Your guests will love it!

Overhead view of the sheet cake, sliced in squares.

Ingredient Notes:

Cake Flour – Using cake flour makes this super soft and moist!
Sugars – A combo of brown and granulated sugars.
Sour Cream – The dairy I used here, but plain Greek yogurt works too.
Oil – I used canola oil. If you’d rather, try melted butter instead.
Spices – A combo of cinnamon, nutmeg, and ginger!
Bananas – You’ll need a full two cups of mashed (or pureed) bananas. So probably five to six medium bananas. Make sure they are over-ripe!
The Frosting – A simple caramel frosting consisting of butter, brown sugar, milk, vanilla, and sifted powdered sugar.

The ingredients for the banana sheet cake.

How to make the BEST Banana Sheet Cake:

Step 1
Puree bananas. Use a hand mixer to puree the over-ripe bananas. A few lumps are ok!

You can also use a fork and just mash the bananas instead. Try to get them pretty soft!

Six over-ripe bananas on a white background.

A bowl of the pureed bananas, with a hand mixer.

Step 2
Mix wet ingredients. In the mixing bowl (with the mashed bananas), add the remaining wet ingredients – the oil, eggs, sour cream, and vanilla. Blend with the mixer or with a whisk.

Step 3
Mix dry ingredients. In another bowl, combine the dry ingredients – the cake flour, brown sugar, granulated sugar, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger. Stir to combine.

Step 4
Combine. Add the dry ingredients to the wet, and use a spoon to mix until just combined. A few lumps are ok!

A bowl of the wet ingredients - oil, eggs, sour cream, vanilla, etc.

A bowl of the dry ingredients - flour, sugars, spices, etc.

Step 5
Pour batter in sheet pan. Prep a jelly roll pan with baking spray, and pour the batter inside, spreading evenly to all sides of the pan with a spoon.

Step 6
Bake cake. Bake the banana sheet cake in a preheated 350 degree oven for 25-30 minutes, or until done in the middle. I recommend testing with a toothpick! Set aside to cool.

A sheet pan with the banana cake batter spread out.

Step 7
Make icing. While the cake is baking, make the Old Fashioned Caramel Icing. In a saucepan, melt butter. Add the brown sugar and stir until combined. Then add the milk and bring to a slow boil. Remove from heat and add the vanilla and powdered sugar and mix well.

Let frosting sit for a bit to thicken. (If it gets too thick to spread, you can thin with a few more drops of milk.)

The frosting with powdered sugar added to the top.

Step 8
Add frosting to cake. Add the caramel frosting to the cooled cake, and spread gently to all sides of the pan. Add a light sprinkling of kosher salt to the top.

The frosting should be very easy to spread. If not, add a few drops of milk to thin it just a bit.

A sheet pan of the finished banana cake with caramel frosting.

Step 9
Slice and serve. Slice the cake into 24 equal squares. Serve with or without a scoop of ice cream!

NOTE: If you have big eaters, cut the squares into larger ones! My boys gobbled this up!

For a smaller banana recipe, try my Banana Donuts next!

Recipe Tips and Tricks

Use cake flour OR all-purpose flour. The cake flour adds a super soft texture, but all-purpose flour works well too.
Puree bananas. I like to puree the bananas with a hand mixer. You can also just mash well with a fork.
Don’t over-mix. Make sure you don’t over-mix the batter. Some lumps are ok!
Watch oven closely at end of baking time. All ovens are different so make sure you don’t over-bake this cake. I recommend using a toothpick and insert in the middle of the cake to check for doneness. (If the toothpick comes out clean, it’s done!)
Sift the powdered sugar. I always sift powdered sugar to avoid large clumps.
Make sure the frosting is easily spreadable. You may need to add a few extra drops of milk to make the frosting spread easily. If it’s too stiff, it will make the top of the cake pull away!

Storing and Freezing

You can STORE this cake on your counter top for up to five days. Just cover the pan with foil and try to tent it slightly (so the frosting stays in tact).
Banana Sheet Cake can be FROZEN too, for up to a month. Just wrap the baked (and unfrosted) cake wrapped up tightly in wrap and foil. I recommend frosting the cake later.

Three small plates of the banana cake with forks.

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xoxo ~Sue