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Sweet Potato Sheet Cake with Marshmallow Frosting

This Sweet Potato Sheet Cake is so moist, tender and flavorful with a lovely hint of spice, but the fluffy marshmallow frosting is what sends this cake over the top!
Prep Time20 mins
Cook Time30 mins
Total Time50 mins
Course: Cakes/Cupcakes, Dessert
Cuisine: American, Dessert
Servings: 15 -18
Author: Hayley Parker, The Domestic Rebel


  • cups granulated sugar
  • 15 ounces (One 15-ounce can) sweet potato puree (just plain puree, not pie filling)
  • 1 cup canola or vegetable oil
  • 2 tsp vanilla extract
  • 4 large eggs
  • 2 cups all-purpose flour
  • 2 tsp baking powder
  • 1 tsp baking soda
  • 2 tsp ground cinnamon
  • 1/2 tsp ground nutmeg
  • 1/2 - 1 tsp ground ginger
  • Pinch salt
  • 1/2 cup salted butter softened
  • 7 ounces (One 7-ounce jar) marshmallow fluff or cream
  • 1 tsp vanilla extract
  • 3 cups confectioners' sugar
  • 1/4 cup milk or heavy cream, if needed (may not use)
  • 1 cup toffee bits


  • Preheat oven to 350 degrees F. Liberally grease a 13x9" rectangular baking pan with cooking spray and set aside briefly.
  • In a large bowl with an electric mixer, beat together the granulated sugar and sweet potato puree until blended. Carefully beat in the oil and vanilla, then the eggs one at a time, beating well after each addition.
  • Meanwhile, in a separate bowl, whisk together the flour, baking powder, baking soda, spices, and salt. Gradually add in the flour mixture to the wet mixture, beating well until batter is smooth and combined. Pour the batter into the prepared pan and smooth out the top. Bake for approximately 25-30 minutes or until a toothpick inserted near the center comes out clean or with moist - not wet - crumbs. Cool completely.
  • For the frosting: In the bowl of a stand mixer, cream together the butter and marshmallow fluff until combined, about 1 minute. Beat in the vanilla and gradually begin adding in the confectioners' sugar, about one cup at a time, until frosting is light and fluffy. If frosting is too thick, add in a little of the milk or heavy cream to thin it out. You want the frosting to be spreadable, so not too thick.
  • Spread the frosting onto the cooled cake in an even layer. Sprinkle with toffee bits and serve. Store leftovers either in the fridge or at room temperature, but covered either way.