Description
This Sweet Potato Sheet Cake with Marshmallow Frosting is soft, moist, and perfectly spiced with warm cardamom and cinnamon. Topped with a fluffy marshmallow frosting and optional toasted nuts, it’s a festive dessert that’s perfect for holidays or special gatherings.
Ingredients
Scale
- 1 1/2 pounds (680g) sweet potatoes (4 to 5 medium)
- 1 tablespoon (14g) water
- 2 1/2 cups (300g) all-purpose flour (or 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 vanilla extract
- 6 drops yellow natural food coloring (optional)
- 4 drops red natural food coloring (optional)
- 1 1/4 cups (248g) granulated sugar (for topping)
- 6 large egg whites (180g to 210g), room temperature
- 1 tablespoon (14g) vanilla extract (for topping)
- 1/2 teaspoon table salt (for topping)
- 1/8 teaspoon cream of tartar or lemon juice
- 1/4 cup (29g) pecans or walnuts, diced and toasted (optional)
Instructions
- Preheat oven to 350°F (175°C). Grease and line a 9×13-inch baking pan.
- Peel and chop sweet potatoes. Place in a saucepan with 1 tablespoon water, cover, and steam until tender. Mash or purée until smooth. Measure out 1 3/4 cups (420g) for the cake.
- In a medium bowl, whisk together the flour, baking powder, baking soda, cardamom, cinnamon, and salt.
- In a large bowl, mix melted butter, sugar, sweet potato purée, orange juice, egg yolks, vanilla, and optional food coloring until smooth.
- In a clean bowl, beat egg whites until soft peaks form. Gently fold into the batter.
- Pour batter into prepared pan and bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Let cool completely.
- For the marshmallow frosting: In a heatproof bowl set over simmering water, whisk sugar, egg whites, salt, and cream of tartar until sugar dissolves and mixture reaches 160°F (71°C). Remove from heat and beat with an electric mixer until stiff, glossy peaks form. Add vanilla and mix until combined.
- Spread marshmallow frosting over the cooled cake. Top with toasted nuts if desired. Slice and serve.
Notes
- Sweet potatoes can be roasted instead of steamed for a richer flavor.
- Food coloring is optional but helps achieve a warm orange hue.
- Toast the nuts before topping to enhance flavor and crunch.
- Cake can be stored covered at room temperature for up to 2 days, or refrigerated for up to 5 days.
Nutrition
- Serving Size: 1 slice
- Calories: 360
- Sugar: 35g
- Sodium: 260mg
- Fat: 14g
- Saturated Fat: 8g
- Unsaturated Fat: 5g
- Trans Fat: 0g
- Carbohydrates: 52g
- Fiber: 2g
- Protein: 5g
- Cholesterol: 70mg
Keywords: sweet potato cake, sheet cake recipe, marshmallow frosting, holiday dessert, spiced cake