Sweet Potato Cake with Toasted Marshmallow Frosting Recipe

By
María del Mar Cuadra
A headshot of Maria del Mar Cuadra, a contributing writer at Serious Eats.
María del Mar Cuadra
María del Mar Cuadra is a food stylist, recipe developer, and art director. She has written three cookbooks and worked for America's Test Kitchen.
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Updated August 30, 2018
sweet potato cake with marshmallow frosting

Instead of those puffed up mini-marshmallows, this Ode to a Casserole Cake is mounded with a spiced and spiked, pecan-flecked Italian meringue frosting that bronzes and crisps under the blaze of a hot flame.

Recipe Details

Sweet Potato Cake with Toasted Marshmallow Frosting Recipe

Active 90 mins
Total 4 hrs 30 mins
Serves 12 to 15 servings
Cook Mode (Keep screen awake)

Ingredients

  • For the Sweet Potatoes:
  • 2 ½ pounds sweet potatoes, peeled and cut crosswise into ½-inch thick slices
  • 1/2 cup orange juice
  • 4 tablespoons (2 ounces) unsalted butter, melted
  • 1/4 cup packed dark brown sugar
  • 1/4 cup bourbon
  • 1/4 teaspoon salt
  • For the Cake:
  • 1 tablespoon unsalted butter, softened
  • 3 cups all-purpose flour
  • 3 tablespoons orange juice and 1 tablespoon finely grated orange zest
  • 2 teaspoons ground cinnamon
  • 1 teaspoon ground ginger
  • 1 teaspoon ground allspice
  • 1 teaspoon baking soda
  • 3/4 teaspoon salt
  • 1 cup sugar
  • 1 cup packed dark brown sugar
  • 3 large eggs, at room temperature
  • 1 1/2 cups vegetable oil
  • 1/4 cup bourbon
  • 2 teaspoons pure vanilla extract
  • For the Toasted Marshmallow Frosting:
  • 1 1/3 cups sugar
  • 1/2 teaspoon ground cinnamon
  • 1/2 teaspoon ground ginger
  • 1/2 teaspoon ground allspice
  • ¼ cup bourbon
  • 2 tablespoons light corn syrup
  • 6 large egg whites, at room temperature
  • 1/4 teaspoon salt
  • 2 cups toasted pecans, chopped

Directions

  1. For the Sweet Potatoes: Adjust oven rack to middle position and preheat oven to 375°F (190°C). Arrange sweet potato slices in foil-lined 13- by 9-inch baking dish or foil-lined rimmed baking sheet.

  2. In medium bowl whisk together orange juice, melted butter, brown sugar, bourbon, and salt. Pour mixture over sweet potatoes and bake until they’re tender and syrupy, about 1 hour, stirring to coat in liquid every 15 minutes.

  3. Transfer dish to cooling rack and cool sweet potatoes for 10 minutes. Pulse sweet potatoes and any syrup in food processor until smooth. Measure out 2 cups and transfer to bowl; cool to room temperature, about 15 minutes.

  4. Reduce oven temperature to 350°F (180°C).

  5. For the Cake: Grease a 13- by 9-inch baking dish with butter.

  6. In medium bowl, whisk together flour, orange zest, cinnamon, ginger, allspice, baking soda, and salt.

  7. In separate large bowl, beat sugar, dark brown sugar, and eggs on medium speed until thickened and lightened in color, about 2 minutes. With mixer running, slowly add orange juice, oil, bourbon, and vanilla. Reduce speed to low and add flour mixture in three additions, alternating with sweet potatoes. Mix just until combined, scraping down sides and bottom of bowl with rubber spatula as needed.

  8. Pour batter into prepared baking dish and bake until toothpick inserted in middle of cake comes out clean, about 1 1/2 hours. Transfer cake to cooling rack and cool completely in pan, 1 1/2 to 2 hours.

  9. For the Toasted Marshmallow Frosting: Stir sugar, cinnamon, ginger, allspice, bourbon, and corn syrup in large heavy-bottomed saucepan over medium-low heat until sugar dissolves. Increase heat to medium-high and boil syrup until it registers 238°F. on candy thermometer, 8 to 10 minutes.

  10. While syrup boils, in large bowl, beat egg whites and salt with whisk attachment on medium-low speed until whites begin to loosen and froth, about 1 minute. Increase speed to medium-high and beat whites until soft peaks form, 1 to 2 minutes.

  11. With mixer running on medium-high speed, slowly and carefully add syrup to egg whites. Beat until outside of bowl is cool to the touch and whites are thick and glossy, about 7 minutes. Fold in pecans.

  12. Spread topping on cooled cake with a spatula, pulling up on meringue to create decorative peaks. Torch meringue to lightly toast. If you don’t have a torch, adjust oven rack to upper third and set oven to broil. Broil until golden, 1 to 2 minutes.

Special equipment

Foil, 13- by 9-inch baking dish, (optional) large rimmed baking sheet, cooling rack, food processor, electric mixer, rubber spatula, large heavy-bottomed saucepan, candy thermometer, pastry torch (optional)

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