A rich, spiced sweet potato cake is easily layered with a soft marshmallow buttercream. This is a perfect cake to say goodbye to fall and welcome in winter.
By Valentina Celant
I have been wanting to make an unusual recipe with the sweet potato + marshmallow combo for ever, and I just love how this came out! I present to you… sweet potato layer cake with marshmallow buttercream! I made some sweet potato cookies last year, and now, cake! You’re gonna love this. 
This recipe starts with a spiced sweet potato cake that’s rich and dense, and is stuffed with a light and fluffy 5-minute marshmallow buttercream that is to-die-for. I’m honestly not a big fan of the classic holiday side dish, but I will happily admit yams and marshmallows are the perfect combination!
- *for the cake*
- 1¾ cups mashed sweet potato {about 2 medium yams}
- 2¾ cups all-purpose flour
- 1 tsp baking powder
- 1 tsp baking soda
- 2 tsp pumpkin spice mix
- 1¼ cups white sugar
- ¾ cups brown sugar
- ½ cup {1 stick} unsalted butter, softened
- ½ cup vegetable oil
- 4 eggs
- 2 tsp vanilla extract
- ¾ cups whole milk
- pinch of salt
- *for the frosting*
- 1 cup {2 sticks} unsalted butter, softened
- 1 7oz jar marshmallow creme
- 2 cups powdered sugar
- 1 tsp vanilla extract
- 1-2 tbsp milk
- First, make the cakes. Heat the oven to 350F, and grease & flour 4 6-inch cake pans {or 3 9-inch pans}.
- In the bowl of a stand mixer, beat together the butter and sugars until light and fluffy. Mix in the oil. Add in the eggs, one at a time, beating until each addition, and finally stir in the vanilla.
- In a medium bowl, mix together the mashed sweet potato and milk until smooth.
- In a separate medium bowl, whisk together the flour, baking powder, baking soda, salt, and pumpkin spice.
- Add half of the dry ingredients into the butter mixture, and mix until combined. Add in the mashed sweet potato mixture and mix again, then add in the remaining dry ingredients.
- Divide the cake batter evenly among the prepared cake pans, and bake for 40-45 minutes for 6-inch pans, or 30-35 minutes for 9-inch pans.
- Let cakes cool slightly, then remove from pans and let cool completely before frosting.
- When ready to make the frosting, beat the softened butter and marshmallow creme in the bowl of a stand mixer until light and fluffy. Mix in the vanilla and salt, then beat in the powdered sugar ½ cup at a time. Finally, add in milk until the frosting is as stiff or soft as needed!
- Frost cake as desired, and serve!
I love the recipes and make a lot of them. They aren’t always complete. If if calls for brown sugar it doesn’t say dark or light. The sweet potato Marshmallow cake doesn’t say how to use the marshmallows to get it to look like the photo. I made the pumpkin bundt cake with brown butter and maple syrup glaze it was good but,
way to much powdered sugar . I find the recipes are not very specific. With that being said I love the recipes and will always make them I just hope that they can be a little more specific. Thank you .
Hi Karen! Thank you for your comment! This is my recipe so I can address some of your concerns. Generally, if i don’t specify the type of brown sugar it is because either light or dark will work. As for the decorating of this cake, i decorated it using a Wilton 1A tip which is a large round tip. I piped small dollops around the edges of the layers to give the puffy cloud look. On the very top, i held the piping bag straight up, piped small dollops, and pulled to give the spiked effect. Hope this helps! I’ll make an effort to be more specific in my recipes.