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Sweet Potato Sheet Cake with Marshmallow Frosting Recipe

Sweet Potato Sheet Cake with Marshmallow Frosting Recipe
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★★★★★

4.8 from 27 reviews

This Sweet Potato Sheet Cake is a moist and flavorful dessert featuring a spiced sweet potato batter baked to perfection and topped with a fluffy marshmallow frosting. The cake combines warm spices like cinnamon and cardamom with the natural sweetness of sweet potatoes and orange juice, finished with toasted pecans or walnuts for added texture. It’s a nostalgic, comforting treat perfect for fall or any special occasion.

Ingredients

Scale

Sweet Potato Purée

  • 1 1/2 pounds (about 680g or 24 ounces) sweet potatoes (4 to 5 medium)
  • 1 tablespoon (14g) water, cool

Cake Batter

  • 2 1/2 cups (300g) King Arthur Unbleached All-Purpose Flour or King Arthur Gluten-Free Measure for Measure Flour
  • 1 teaspoon baking powder
  • 1 teaspoon baking soda
  • 1 teaspoon cardamom
  • 1 teaspoon cinnamon
  • 3/4 teaspoon table salt
  • 16 tablespoons (226g) unsalted butter, melted
  • 1 cup (198g) granulated sugar
  • 1 3/4 cups (420g) sweet potato purée, from above
  • 1/2 cup (113g) orange juice
  • 2 large eggs, yolks separated from whites, at room temperature
  • 1 teaspoon King Arthur Pure Vanilla Extract
  • 6 drops yellow natural food coloring, optional
  • 4 drops red natural food coloring, optional

Marshmallow Frosting

  • 1 1/4 cups (248g) granulated sugar
  • 6 large egg whites (180g to 210g), at room temperature
  • 1 tablespoon (14g) King Arthur Pure Vanilla Extract
  • 1/2 teaspoon table salt
  • 1/8 teaspoon cream of tartar or lemon juice
  • 1/4 cup (29g) pecans or walnuts, diced; toasted

Instructions

  1. Prepare the sweet potato purée: Preheat your oven to 400°F with racks placed in the middle and upper third positions. Prick the sweet potatoes several times with a fork or paring knife, place them on a parchment- or foil-lined baking sheet, and bake for 45 to 60 minutes until tender. Once cool enough to handle, slice them in half lengthwise. Reduce oven temperature to 350°F.
  2. Make the purée: Remove the skins from the baked sweet potatoes and transfer the flesh to a food processor bowl. Add 1 tablespoon of cool water and process until very smooth, roughly one minute, stopping to scrape down the sides as needed. Measure out 1 3/4 cups (420g) of purée for the recipe and set aside.
  3. Prepare the pan: Lightly grease a 9″ x 13″ baking pan and line it with parchment paper, then lightly grease the parchment to prevent sticking.
  4. Mix dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, cardamom, cinnamon, and salt. Set aside.
  5. Combine wet ingredients: In a large bowl, whisk the melted butter together with 1 cup granulated sugar until well combined. Add the sweet potato purée and whisk again until smooth.
  6. Add additional wet ingredients: Stir in the orange juice, egg yolks, vanilla extract, and optional food colorings (yellow and red) until evenly incorporated.
  7. Incorporate dry ingredients: Add the dry mix to the wet mixture in two additions, folding gently with a flexible spatula after each addition until combined without overmixing.
  8. Whip egg whites: In a separate small bowl, vigorously whisk the egg whites until foamy and no liquid remains at the bottom. Gently fold the egg whites into the batter until no white streaks remain, maintaining the airy texture.
  9. Transfer and bake: Pour the batter evenly into the prepared pan and smooth the surface. Bake on the middle rack for 35-40 minutes, or until a toothpick inserted into the center comes out clean and the top feels set.
  10. Cool the cake: Allow the cake to cool in the pan on a rack for about 30 minutes. Use the parchment sling to carefully lift the cake out of the pan and cool completely on the rack.
  11. Prepare marshmallow frosting: In a large heatproof bowl or stand mixer bowl, whisk together sugar, egg whites, vanilla extract, salt, and cream of tartar or lemon juice until combined.
  12. Heat the mixture: Place the bowl over simmering water with gentle bubbles, whisking constantly until the mixture reaches 161°F on a digital thermometer, about 5 to 10 minutes. Test by rubbing a bit between your fingertips to ensure sugar is dissolved.
  13. Beat to stiff peaks: Remove bowl from heat and beat with a whisk or mixer attachment on medium-high speed for 10 to 13 minutes until stiff peaks form and the mixture is glossy and thick.
  14. Frost the cake: Spread the marshmallow topping evenly over the cooled cake using the back of a spoon or offset spatula. Create decorative swirls if desired.
  15. Toast the topping and garnish: Use a kitchen torch to toast the marshmallow topping evenly until golden brown edges appear, or place under a broiler on the upper rack and watch carefully to prevent burning. Immediately sprinkle toasted pecans or walnuts over the top before serving.

Notes

  • For best results, use room temperature eggs to ensure better mixing and volume.
  • The orange juice adds brightness and moisture, but can be substituted with apple juice if unavailable.
  • If using gluten-free flour, choose a reliable measure-for-measure blend to maintain texture.
  • Allow the cake to cool completely before frosting to prevent melting the marshmallow topping.
  • Leftovers can be stored covered at room temperature for up to 3 days.
  • To toast nuts, spread them on a baking sheet and bake at 350°F for 5-7 minutes until fragrant.
  • The optional food coloring enhances the cake’s warm color but is purely aesthetic.
  • Be cautious when broiling the frosting as it can burn quickly; a kitchen torch provides better control.

Nutrition

Keywords: sweet potato cake, sheet cake, marshmallow frosting, spiced cake, fall dessert, holiday cake, vegetarian dessert

Find it online: https://thefoodrecipe.com/sweet-potato-sheet-cake-with-marshmallow-frosting-recipe/