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Transform a traditional Thanksgiving side dish into the perfect dessert with this Sweet Potato Cake with Marshmallow Frosting. | livforcake.com
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5 from 3 votes

Sweet Potato Cake with Marshmallow Frosting

Transform a traditional Thanksgiving side dish into the perfect dessert with this Sweet Potato Cake with Marshmallow Frosting.
Course Dessert
Cuisine Cake
Prep Time 2 hours
Cook Time 40 minutes
Total Time 2 hours 40 minutes
Servings 12
Calories 618kcal
Author Olivia

Ingredients

Sweet Potato Cake:

Marshmallow Fluff:

Instructions

Sweet Potato Cake:

  • Preheat oven to 350F and grease & flour two 8" cake pans.
  • In a medium bowl, whisk together flour, cinnamon, nutmeg, baking powder, and salt.
  • In a large bowl, whisk together sugars, melted butter, oil, sweet potato, and eggs.
  • Add dry to wet and mix until just combined.
  • Divide batter evenly between prepared pans and bake until a toothpick inserted into the center comes out mostly clean (approx. 35-40 mins).
  • Cool in pans on wire rack for 10mins, then turn out onto wire racks to cool completely.

Marshmallow Fluff:

  • Place water, sugar, and corn syrup in a medium saucepan. Stir to combine.
  • Insert a candy thermometer into the pot and heat over medium-high. Do not stir from this point on as crystals will form.
  • Ensure mixer bowl and whisk are completely grease free.* Place egg whites and cream of tartar in the bowl of a stand mixer. 
  • When the sugar syrup reaches about 225°F, start whipping the egg whites to soft peaks. 
  • When the whites are ready, the sugar syrup should be at 240°F. Remove from the heat, turn mixer to medium and very slowly and carefully pour the sugar syrup into the whites in a thin, steady stream.**
  • Once all of the syrup is in, set mixer to medium/high and continue whipping. The whites will deflate at first, but they will thicken and fluff up.
  • Continue to whip for 7-8 minutes, or until the mixture is thick and glossy. Add in vanilla and whip until the fluff has cooled.

Assembly:

  • Place one layer of cake onto a serving plate or cake stand. Top with 1 cup marshmallow fluff. Spread evenly. It will be thick and sticky.
  • Place remaining layer on top and do a thin coat of marshmallow all around the cake, just to hide any dark bits of cake.
  • Using a 1M piping tip. Pipe rosettes along the sides and top of the cake. Torch with a kitchen torch if desired.***

Notes

* If there is even a speck of grease (or egg yolk) the meringue will not whip. I wipe everything down with lemon juice before adding the egg whites.
** The sweet spot for this is getting the stream right between the whisk and the sides of the bowl, so the syrup doesn't get splashed by the whisk.
*** The torching will help set the marshmallow. Ideally serve same day as the marshmallow fluff inside the cake will soften and turn runny. This is not bad, by any means, but maybe less aesthetically pleasing.

Nutrition

Calories: 618kcal | Carbohydrates: 120g | Protein: 6g | Fat: 14g | Saturated Fat: 9g | Cholesterol: 61mg | Sodium: 238mg | Potassium: 398mg | Fiber: 1g | Sugar: 94g | Vitamin A: 6970IU | Vitamin C: 6.8mg | Calcium: 91mg | Iron: 1.9mg