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Southern Sweet Potato Cake with Marshmallow Frosting is the perfect cake for fall & Thanksgiving. It’s moist, filled with warm spices, and topped with a sweet fluffy cloud of marshmallow buttercream!

2 slices of sweet potato cake with marshmallow frosting and the pan of cake in the background.
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You’ve probably tried spice cake, and you’ve definitely tried carrot cake – but have you ever had sweet potato cake? It’s a delicious Southern favorite that you need to add to your baking list.

It’s a moist spice cake that’s perfectly dense with the perfect hint of cinnamon. Then to remind you of sweet potato casserole, it’s topped with fluffy cream cheese frosting.

Now I love sweet potato as much as the next person. Sweet potato fries, mashed sweet potato, sweet potato hashbrowns – you name it. But I had never tried baking with sweet potato until recently. It turns out that it’s delicious. It adds so much moisture to baked goods so they end up soft, tender, and perfectly dense without being heavy.

weet potato cake with marshmallow buttercream made in a 9 x 13 inch pan.

Plus – the flavor tastes delicious with brown sugar and cinnamon. It’s really a very similar idea to baking with pumpkin or carrots. Totally delicious.

Sweet Potato Cake with Marshmallow Frosting

Southern sweet potato cake is a moist spice cake that's topped with marshmallow frosting.

I decided to make this sweet potato cake as a sheet cake in a 9×13 inch pan because it’s way less work than making a layer cake, and I feel like a sheet cake version works better with such a dense cake. 

The cake itself is crazy moist because of a few key ingredients: oil, eggs, sweet potato, and milk. We’re actually using mashed sweet potatoes/sweet potato puree for this recipe. You can either boil them first, then remove the skins and mash them (or put them in the blender). Or you can buy sweet potato puree (often in the baby food aisle). Just make sure its 100% sweet potatoes – we don’t want any garlic or onion in there.

Then the sweet potato cake has a delicious spice cake flavor thanks to using brown sugar, vanilla extract, cinnamon, and nutmeg. It’ll definitely remind you of spice cake, carrot cake, or pumpkin cake – but I think I might actually prefer the flavor of this sweet potato cake. It’s lightly spiced and not too overwhelming – which I think is delicious.

Then there’s marshmallow frosting to top it all off. It’s made with marshmallow fluff from the jar so it’s super easy, and it tastes like a delicious cloud of marshmallow heave. I added a few chopped pecans on top of my cake – but that’s totally up to you.

A large slice of sweet potato cake with a bite eaten out of it.

This sweet potato cake with marshmallow frosting is the perfect dessert for fall or Thanksgiving – or if you love carrot cake and are looking for a delicious alternative.

If you love this sweet potato cake, make sure to try these other fall favorites:

A close up of Sweet Potato Cake with Marshmallow Frosting

Sweet Potato Cake with Marshmallow Frosting

5 from 3 votes
Southern Sweet Potato Cake with Marshmallow Frosting is the perfect cake for fall & Thanksgiving. It’s moist, filled with warm spices, and topped with a sweet fluffy cloud of marshmallow buttercream!
Prep Time 30 minutes
Cook Time 40 minutes
Total Time 2 hours 10 minutes
Servings 15 servings


Sweet Potato Cake

  • 2 1/4 cups all-purpose flour
  • 2 teaspoons cinnamon
  • 1/2 teaspoon nutmeg
  • 1 teaspoon baking soda
  • 1 teaspoon baking powder
  • 1/2 teaspoon salt
  • 1/2 cup vegetable oil
  • 1 cup white sugar
  • 3/4 cup brown sugar
  • 2 teaspoons vanilla extract
  • 3 large eggs
  • 2 cups mashed/pureed sweet potato
  • 1/2 cup milk

Marshmallow Frosting

  • 2/3 cup unsalted butter softened
  • 7 ounces Marshmallow fluff
  • 2 cups powdered sugar add more if needed
  • 1 tablespoon heavy cream or milk; add more as needed
  • 1/4 cup chopped pecans optional
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Sweet Potato Cake

  • Preheat the oven to 350F degrees. Grease and flour a 9×13 inch cake pan.
  • In a medium bowl whisk together the flour, cinnamon, nutmeg, baking soda, baking powder & salt. 
  • In a large bowl beat together the oil, sugars, eggs & vanilla extract until no sugar lumps remain. Then mix in the mashed sweet potato. 
  • With the mixer on low beat in the flour mixture about ½ at a time, alternating with the milk. 
  • Pour the batter into the prepared pan and bake for 40-50 minutes, or until an inserted toothpick comes out clean and the cake doesn’t wobble if you give the pan a nudge.

Marshmallow Frosting

  • In a large bowl beat the butter until fluffy.
  • Then mix in the marshmallow fluff.
  • Mix in the powdered sugar about 1 cup at a time, until the desired sweetness is reached. Then mix in the cream/milk 1 tablespoon at a time.
  • Frost the cooled cake, then optionally decorate with pecans. 
Keyword sweet potato cake


Calories: 407kcalCarbohydrates: 74gProtein: 4gFat: 11gSaturated Fat: 6gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gTrans Fat: 1gCholesterol: 57mgSodium: 185mgPotassium: 277mgFiber: 2gSugar: 51gVitamin A: 7504IUVitamin C: 7mgCalcium: 60mgIron: 1mg

Nutritional Disclaimer Kristin Maxwell of “Yellow Bliss Road” is not a dietician or nutritionist, and any nutritional information shared is an estimate. For accurate calorie counts and other nutritional values, we recommend running the ingredients through your preferred online nutritional calculator. Calories and other nutritional values can vary depending on which brands were used.

Southern Sweet Potato Cake with Marshmallow Frosting is the perfect cake for fall & Thanksgiving. It's moist, filled with warm spices, and topped with a sweet fluffy cloud of marshmallow buttercream!


Fiona blogs over at Just So Tasty where she shares easy, classic recipes for desserts & sweet treats. A peanut butter lover, chocolate connoisseur, and sprinkle addict - she hopes to make your life sweeter, one cookie at a time. She also teaches yoga, because life is all about balance.

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5 from 3 votes (2 ratings without comment)

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  1. Reba Prejean says:

    Can you substitute the icing with cream cheese icing instead? I don’t have marshmallow fluff or marshmallows.

    1. Kristin Maxwell says:

      Sure, you can use any frosting you like.

  2. Taryn says:

    Excellent cake. Baked for 40 minutes and it was perfect. The marshmallow frosting complimented this cake perfectly.

    1. Kristin says:

      Nice! Thanks for stopping by Taryn.

  3. Meems says:

    How long would leftovers last in the fridge? Also, can I bake the sweet potatoes instead of boiling them? Would that make a difference? Thank you!

    1. Kristin Maxwell says:

      Hi, covered in the fridge the cake will last 5 days. You can cook the sweet potatoes any way you like.

  4. Jacque Zannini says:

    Would almond milk substitute for the milk?
    Thank you

    1. Kristin Maxwell says:

      Almond milk would be sweeter, so you might want to reduce the sugar just a little.

  5. Renee says:

    Can you use Bruce’s mashed sweet potatoes

    1. Kristin Maxwell says:

      If it equals 2 cups and it’s 100% pure sweet potato, sure.

  6. Karen Burbage says:

    I made the cake but used a cream cheese maple buttercream. It. Is. DELICIOUS.

    1. Kristin says:

      Nice! Thank you so much Karen for stopping by.

  7. Sharon says:

    As a true Southern girl, I have always believed that “anything a pumpkin can do, a sweet potato can do BETTER”! Love this idea.

    1. Kristin says:

      Sharon, So glad you enjoyed it!
      Thank you for stopping by!

  8. Judy Glotfelty says:

    Sounds yummy and plan to make this weekend. Thanks ?

    1. Kristin says:

      Thanks Judy,
      Thank you for stopping by!

  9. Snegolenka says:

    What an interesting recipe! And the ingredients are all in my kitchen! I’ll cook today! I will rejoice my family! Thank you for what you inspire to create culinary masterpieces.