This Sweet Potato Casserole Cake boasts sweet potato cake layers, a brown butter brown sugar filling and a toasted marshmallow fluff meringue frosting. A perfect Thanksgiving cake idea based on your favorite sweet side dish.
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The inspiration for this Thanksgiving layer cake came from being overwhelmed by the amount of pies and pumpkin desserts that come around this time of year. I wanted something a little different, but still true to the holiday. The lovely toasted meringue frosting is adapted from Liv for Cake.
I have always loved layer cakes, but lately my jam has been 8-inch two layer cakes. I fell in love with this style when I made my Blueberry Layer Cake. I love them because they are much less overwhelming than super tall layer cakes. Another low effort layer cake is my Chamomile Strawberry Layer Cake.
Ingredients
Sweet potato is the star of this cake, but I couldn’t forget the butter and brown sugar that typically accompany a sweet potato casserole.
- all-purpose flour
- baking powder
- baking soda
- cinnamon
- light brown sugar
- granulated sugar
- eggs
- vegetable oil
- sweet potato
- vanilla
- unsalted butter
- heavy cream
- powdered sugar
- cup corn syrup
- cream of tartar
See recipe card for quantities.
Instructions
Here’s how to build the cake:
Place the first layer of cake on the cake board. Pipe and spread filling on top of the first layer.
Place the second layer on top of the filling.
Pipe marshmallow meringue fluff onto cake and spread with an offset spatula. Make swoops and swirls using the tip of the spatula.
Toast the meringue with a kitchen torch.
Good to know: I found that going slower when frosting the cake made smoother swirls, rather than flicking the offset spatula too quickly, which gave a dimpled look.
Substitutions
Here are some easy ingredient swaps if you want to make this cake dairy-free:
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- Butter — use dairy-free butter
- Heavy cream — use full-fat coconut milk
Variations
Here’s how to customize this cake to your liking:
- Skip browning butter — Skip browning your butter for less work. Just melt the butter, brown sugar, cream and vanilla together for the filling.
- Buy store bought fluff — You can also use store-bought marshmallow fluff to frost this cake instead of making your own.
- More spices — Add ½ teaspoon ginger and nutmeg for even more fall spice.
Do you have any other variation suggestions? Let me know in the comments!
Equipment
I used an 8-inch cake board to build the cake. You can also just build the cake on the platter or cake stand you plan to serve it on, but I find it helpful to use a cake board so I can easily transfer the cake from the cake turntable to the serving platter to the cake carrier for storage.
I used piping bags to transfer the frosting onto the cake before spreading. You can also just spread it on with an offset spatula.
For me, whipping the meringue frosting was made so much easier by using my Kitchenaid Stand Mixer. But you can also use hand beaters.
I bake my cake layers in tins wrapped with bake-even strips to prevent domed tops.
You’ll need a kitchen torch to toast the meringue, if desired.
Storage
Store cake at room temperature (the meringue frosting is shelf stable) in an airtight container for 3-4 days.
Baked cake layers tightly wrapped in plastic in an airtight container can be frozen for up to one month.
Top tip
Make sure ingredients are at room temperature for easier mixing and even baking.
Lastly, if you make this Sweet Potato Casserole Cake be sure to leave a comment or give this recipe a rating. I love to see when people make my recipes, so please tag me @youthsweets on Instagram if you post!
📖 Recipe
Sweet Potato Casserole Cake
Equipment
Ingredients
Sweet potato cake
- 2 ¾ cups all-purpose flour (336g)
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- ½ teaspoon salt
- 1 tablespoon cinnamon
- ¾ cup packed light brown sugar (165g)
- ⅔ cup granulated sugar (140g)
- 3 large eggs
- 1 cup vegetable oil
- 2 cups cooked and mashed sweet potato cooled (about 4-5 large sweet potatoes, or a bag of small sweet potatoes) (465g)
- 2 teaspoons vanilla bean paste or vanilla extract
Brown sugar filling
- ½ cup unsalted butter
- ¾ cups light brown sugar packed (170g)
- 5 tablespoons heavy cream
- ½ teaspoon vanilla
- 2 cups powdered sugar (240g)
- salt
Marshmallow fluff meringue frosting
- ⅓ cup water
- ¾ cup granulated sugar (157g)
- ¾ cup corn syrup (245g)
- 3 large egg whites room temperature (90g)
- ½ teaspoon cream of tartar
- 1 teaspoon vanilla extract
Instructions
Do ahead
- Preheat the oven to 350°F. Grease two 8-inch round cake tins and place circles of parchment paper in the bottoms.
Make the cake layers
- Whisk together the flour, baking powder, baking soda, salt and cinnamon. Set aside.
- In another bowl, combine the brown sugar, granulated sugar, eggs, oil, mashed sweet potatoes and vanilla.
- Add the dry ingredients to the wet ingredients and mix just until combined. Do not overmix.
- Split the batter evenly between the prepared pans.
- Bake for 25-35 minutes. A toothpick or cake tester should come out clean, when it is done.
- Let cool in the tins for 20 minutes before tipping out onto a wire rack to cool completely.
Make the filling
- In a medium saucepan over medium heat brown the butter. This may take a few minutes. The butter will become foamy and sputter. Pull it from the heat as soon as you see the milk solids take on a brown, nutty color. Transfer to a heat proof bowl.
- Add the cream, brown sugar and vanilla to the bowl. Microwave in bursts until the sugar is dissolved. Allow to cool completely.
- In the bowl of a stand mixer, or with hand beaters, beat together the cooled mixture with the powdered sugar.
Make the marshmallow fluff frosting
- Prep your mixing bowls and beaters by wiping them down with vinegar to ensure they are oil-free so the meringue doesn’t fail.
- Place water, sugar and corn syrup in a medium saucepan over medium-high. Stir to combine and then do not stir any longer to prevent crystals forming.
- Place the egg whites and cream of tartar in the bowl of a stand mixer.
- When the sugar syrup reaches 225°F, start whipping the egg whites on medium-low.
- When the sugar syrup reaches 240°F, remove it from the heat. Turn the mixer to medium and slowly stream in the sugar syrup into the whites.
- When the syrup is in, turn the mixer to medium-high and continue whipping for 7-8 minutes, or until the mixture is thick and fluffy.
- Add in the vanilla and whip until the fluff cools completely.
- Use right away or transfer into an airtight container and store for up to 2 weeks at room temperature.
Assemble the cake
- Trim the tops of the cakes to be flat, if necessary.
- Place the first layer of cake onto an 8-inch cake board or cake platter with a small smear of the frosting or filling to hold it in place.
- Pipe or spread the brown butter brown sugar filling on top of the first cake layer, using as much or as little as you’d like.
- Place the top layer of cake on top of the filling. Give the cake a gentle press on top to push the cake into the filling.
- Pipe or spread the marshmallow meringue fluff all over the cake, smoothing with an offset spatula. Make swoops and swirls in the frosting with the tip of the offset spatula or with the back of a spoon.
- Use a kitchen torch to toast the outside of the cake, if desired.
