Sweet Potato Cake with Marshmallow Meringue
Sweet Potato Cake with Marshmallow Meringue is a pillowy soft slice of heaven. Perfectly seasoned with your favorite fall spices, this sheet cake is topped with a thick layer of homemade marshmallow frosting.
Ingredients
Sweet Potato Sheet Cake
- 2 cups all-purpose flour unbleached
- 2 tsp baking powder
- 1 tsp baking soda
- 3 tsp cinnamon
- 1 tsp ginger
- 1/2 tsp nutmeg
- 3/4 tsp sea salt fine
- 1 cup unsalted butter softened to room temperature
- 1 cup dark brown sugar packed
- 1/2 cup granulated sugar
- 4 large eggs room temperature
- 2 cups mashed sweet potatoes room temperature
- 2 tsp vanilla extract pure
Marshmallow Meringue
- 6 large egg whites
- 1 1/2 cups granulated sugar
- 3/4 tsp cream of tartar
- 1 1/2 tsp vanilla extract pure
- 1/8 tsp sea salt fine
Instructions
Sweet Potato Sheet Cake
- Preheat oven to 350 degrees. Grease and flour the bottom and sides of a 9 x 13 baking pan.
- In a large mixing bowl, whisk together flour, baking powder, baking soda, cinnamon, ginger, nutmeg and salt. Set aside.
- In a separate bowl, use and electric mixer to beat butter and both sugars until creamy smooth – approximately 2 to 3 minutes.
- Add eggs, one at a time, beating after each addition until incorporated. Scrape down the sides of the bowl with a spatula as needed.
- Beat in sweet potatoes and vanilla extract until smooth and lump free.
- Reduce mixer speed to low. Add dry ingredients to wet, beating until just combined. Take care to not overmix.
- Pour batter into baking pan then smooth the top with a spatula.
- Bake for 30 to 35 minutes or until a tester inserted into the center comes out with a few moist crumbs. Avoid overbaking.
- Remove pan from oven and place on a baking rack to cool completely before frosting.
Marshmallow Meringue
- Using a double boiler, bring an inch or two of water to a simmer. Continuously whisk egg whites and sugar over heat until sugar has completely dissolved, approximately 7 minutes.
- Immediately transfer marshmallow meringue to a clean mixing bowl and beat with an electric mixer until soft peaks form, approximately 5 minutes.
- Add cream of tarter, vanilla and salt and continue beating until stiff peaks form, approximately 10 to 12 minutes.
- Spread frosting onto cooled cake.*Note: this recipe makes a thick layer of meringue. If you prefer a thinner layer of frosting, cut the recipe in half.
- Toast marshmallow meringue with a blow torch until golden brown (or under an oven broiler for 1 to 2 minutes) until golden brown.
- Place cake in the refrigerator to chill until frosting sets then slice and serve.
- Note: Frosting will begin to wilt if left at room temperature. To prevent wilting, cover and chill cake in the refrigerator up to 2 days.