Soft Sweet Potato Cake with Mascarpone Frosting
A soft, spiced sweet potato sponge layered with lush brown butter mascarpone frosting—whether you’re baking for a fall gathering, Thanksgiving dessert table, or simply craving a cozy cake, this sweet potato cake delivers comfort and decadence in every bite!
Sweet Potato Cake with Brown Butter Cream Cheese Frosting
If carrot cake is a classic, consider this sweet potato cake its softer, more luxurious cousin. Thanks to roasted sweet potatoes, the sponge is impossibly moist, with a plush crumb and sturdy texture. The recipe is somewhat similar to pumpkin bread, but (in my opinion) has a much better flavor!
Roasting the sweet potatoes concentrates their natural sweetness and gives the cake density (in a good way), while whipped egg whites keep the crumb light and warm spices pull everything together. I decorated mine with homemade fudge frosting (the method for this element is a bit technical, so I left it out of an already lengthy recipe!), and if that’s not enough, the whole cake gets topped off with a silky brown butter mascarpone frosting. It’s decadent, delicious, full of fall flavor, and basically heaven on a plate!
What is Sweet Potato Cake?
Sweet potato cake is similar to carrot cake or pumpkin bread, but with a naturally sweeter, silkier crumb. Instead of relying on canned purée, this recipe uses roasted sweet potatoes, which concentrates their flavor and removes excess moisture. The addition of whipped egg whites add lightness, and a few spices like cinnamon, ginger, and nutmeg compliment the sweet potato.
Why You’ll Love This Recipe
- Ultra-moist crumb thanks to a combination of roasted sweet potato, oil, and sour cream.
- The brown butter mascarpone frosting. It’s one of my favorites, combining nutty, caramelized butter with creamy mascarpone for a frosting that’s luxurious but not overly sweet.
- A great alternative to pumpkin bread. I know not everyone loves pumpkin, but sweet potato is the perfect alternative!
- Perfect showstopper for special occasions.
Ingredients You’ll Need
I won’t lie and say that this recipe is quick and easy. It requires quite a few bowls (four, to be exact), plus some ingredients like mascarpone that you might not readily have on hand, but I promise it’s worth it! Here’s everything you need to make it:
- Light brown sugar.
- Granulated sugar.
- Eggs.
- Vegetable oil.
- Roasted sweet potato purée.
- Sour cream and whole milk.
- Vanilla extract
- Cake flour.
- Baking soda + baking powder.
- Ground cinnamon, ginger, and nutmeg.
- Kosher salt and cream of tartar.
- Unsalted butter.
- Mascarpone cheese and powdered sugar (for the frosting).
How to Make Sweet Potato Cake
- Roast the sweet potatoes. To make the purée, roast the potatoes until fork-tender, then cool and mash until smooth. Roasting deepens the flavor and avoids adding excess moisture to the cake.
- Brown the butter until golden and nutty, then chill until solid but spreadable. If you don’t want to do this step, you can skip it, but I personally love the extra toastiness and depth that brown butter lends to the cake. For more tips on how to brown butter, check out my brown butter chocolate chip cookie recipe!
- Mix the dry ingredients until well combined and set aside.
- Whip the egg whites to medium peaks—this adds extra structure and lift to the cake layers.
- Prepare the cake batter. Beat together the egg yolks, sugar, and vegetable oil until pale and emulsified, then alternate adding the wet and dry ingredients until just combined.
- Fold in the whipped egg whites. Do this step carefully to keep the batter aerated.
- Bake, cool, and assemble. While the cakes cool, whip together the brown butter, mascarpone, and powdered sugar until smooth, then assemble and decorate the cake as desired.
Recipe FAQs/Recipe Tips + Tricks
- Can I boil the sweet potatoes? No! Roasting the sweet potatoes keeps excess moisture out of the cake and deepens their natural flavor—don’t skip this step!
- Can I use canned sweet potato or pumpkin purée? Unfortunately, no! Fresh roasted sweet potato is best for flavor and texture, and canned purée contains too much extra moisture that will make the cake dense. If you’re in the mood for pumpkin, though, I recommend making my perfect pumpkin bread recipe!
- Why whip the egg whites separately? This technique adds air to the batter and creates a lighter, more delicate crumb. This is especially important for a cake with heavy ingredients like sweet potato and sour cream.
- How do I know when the cake is done? Insert a skewer into the center—it should come out clean or with a few moist crumbs, not wet batter.
Tips for best results:
- Thoroughly blend the sweet potatoes. I use an immersion blender to get the sweet potato purée as smooth as possible, though it’s okay if there are a few small lumps.
- Measure your flour by spooning and leveling. Don’t scoop directly into the flour—this packs it into the cup and adds way too much extra flour. Instead, fluff your flour with a spoon and level off the measuring cup for better accuracy. If you don’t use a kitchen scale when baking, this is easily the most common mistake home bakers make!
- Don’t overmix the batter. You just want to mix until no more streaks of egg white or dry ingredients remain—this ensures that the cakes stays super soft and light after baking.
- Let the cakes cool completely before frosting. Cheese-based frostings are notoriously unstable, which means that they’ll melt even if your cakes are slightly warm. Save yourself the mess by letting the cakes cool completely or by prepping them ahead of time!
Storage & Freezing/Make-Ahead Instructions
Due to the mascarpone cheese frosting, this sweet potato cake needs to be refrigerated. If needed, you can also prep some of the elements ahead of time.
- At room temperature. Without the frosting, the cakes will last about 2 days when wrapped and stored at room temperature.
- Refrigerating. This cake is best enjoyed the day it’s assembled, but will keep for 3 to 5 days in the fridge. Be sure to cover the exposed cake with plastic wrap and store in an airtight container—this ensures that the cake will not dry out or absorb any strong odors from the fridge. Allow to come to room temperature before serving.
- Freezing. Unfrosted cake layers freeze well for up to 3 months. Once baked and completely cool, wrap the individual layers in plastic wrap and foil before freezing. Thaw at room temperature before assembling and decorating.
- Make-Ahead Instructions. You can easily break up this recipe into more manageable pieces. Here’s what can be prepped ahead of time:
- The cake layers can be made one day in advance or frozen for up to 3 months.
- The sweet potato purée can be prepared and stored in the fridge up to 5 days in advance.
- The brown butter for the frosting can be made 1 week ahead of time—simply let it come to room temperature before using in the frosting.
If you make this recipe, be sure to tag me on Instagram or TikTok @gourmae.cafe—happy baking!
Sweet Potato Cake with Cream Cheese Frosting
A soft, spiced sweet potato sponge layered with lush brown butter mascarpone frosting—whether you’re baking for a fall gathering, Thanksgiving dessert table, or simply craving a cozy cake, this sweet potato cake delivers comfort and decadence in every bite!
Print
Pin
Rate
Servings: 14 slices
Ingredients
For the cake batter
- 1 cup (213g) packed light brown sugar
- ½ cup (100g) granulated sugar
- 3 large eggs, separated
- ¾ cup (180g) vegetable oil
- 1 ½ cups (375g) roasted sweet potato, cooled and and puréed (about 3 medium)*
- ⅓ cup (80g) full-fat sour cream, at room temperature
- ⅔ cup (160g) whole milk, at room temperature
- 2 teaspoons vanilla extract
- 2 ½ cups (315g) cake flour, spooned and leveled can substitute with 2 ¼ cups all-purpose flour plus ¼ cup cornstarch
- 1 ½ teaspoons baking soda
- 1 teaspoon baking powder
- 1 ½ teaspoons ground cinnamon
- 1 ½ teaspoons ground ginger
- ¾ teaspoon kosher salt
- ¼ teaspoon ground nutmeg
- ¼ teaspoon cream of tartar (optional, for extra stability)
For the brown butter mascarpone frosting
- 1 cup (227g) unsalted butter
- 8 ounces (227g) cold mascarpone cheese
- 3 cups (375g) powdered sugar, sifted
- 2 teaspoons vanilla extract or vanilla bean paste
- ½ teaspoon kosher salt
- 1-2 tablespoons heavy cream or milk, as needed to thin
Instructions
- Roast the sweet potato. Preheat the oven to 425℉ and line a baking sheet with parchment paper. Scrub, peel, and dice your sweet potatoes into ½ inch cubes, then toss with olive oil and salt. Roast in the oven for 20-25 minutes, or until fork tender. Set aside to cool.
- Brown the butter (for the frosting). In the meantime, add the unsalted butter to a small nonstick pan and melt over medium heat. Continue to cook, stirring frequently, until the mixture foams and begins to toast. Once the butter begins to smell nutty and turn golden-brown, immediately scrape it into a separate bowl. Set in the fridge to cool and solidify as you make the cake.
- Prepare the cakes. Preheat the oven to 350℉. Grease 2 (8-inch) round cake pans with butter. Dust both tins with flour, tapping out the excess, then line the bottoms with a layer of parchment paper. Set aside.
- In a medium bowl, sift together the 2 ½ cups cake flour, 1 ½ teaspoons baking soda, 1 teaspoon baking powder, 1 ½ teaspoons cinnamon, 1 ½ teaspoons ginger, ¾ teaspoon salt, and ¼ teaspoon nutmeg. Mix until evenly incorporated and set aside.
- Once the sweet potato has cooled, use a fork or immersion stick to blend it into a smooth paste. Measure out 1 ½ cups of sweet potato purée and blend with the remaining wet ingredients: ⅓ cup sour cream, ⅔ cup whole milk, 2 teaspoons vanilla extract.
- Separate the eggs and place the whites into a clean bowl with ¼ teaspoon of cream of tartar. Reserve the yolks for later.
- Using a hand mixer or stand mixer fitted with the whisk attachment, beat the egg whites to medium peaks. Do not overmix—when you lift the beater, the meringue should hold a firm, slightly drooped peak but not look dry or lumpy. Set aside.
- Using the same hand mixer (no need to wash the beaters), whip the reserved egg yolks, light brown sugar, and granulated sugar in a bowl on medium speed. With the mixer running, gradually stream in the vegetable oil. Continue to beat the mixture until ribbony, lightened in color, and emulsified, about 3 minutes.
- Wit the mixer on low, add in ⅓ of the dry ingredients and mix until just incorporated. Add in ½ of the wet ingredients and mix. Continue alternating the dry and wet ingredients in three additions, ending with the dry mix.
- Right before the flour is fully incorporated, add one large spoonful of whipped egg whites to the bowl and stir until well combined. Using a rubber spatula, gently fold the remaining egg whites into the batter until fully incorporated and no white streaks remain, being careful not to overmix.
- Divide the batter between the prepared pans, using a silicone or offset spatula to smooth the top. Bake for 30 to 45 minutes, until a skewer inserted in the center of the cake comes out clean or with a few moist crumbs.
- Let the cakes cool for 10 minutes before inverting onto a wire rack. Turn the cakes to sit right side up on the rack, leaving the parchment beneath so the cakes won't stick. Allow to cool completely before assembling.
- Make the frosting. Once the brown butter has solidified, remove it from the fridge to come back to room temperature. Once malleable, place the butter into a bowl and beat with a hand mixer until smooth. Beat in the mascarpone cheese.
- Add the vanilla, salt, and powdered sugar, then mix until a thick frosting forms. If it's too stiff, stir in milk or heavy cream to the desired consistency. If too thin, add more powdered sugar.
- Assemble. If needed, use a serrated knife to level off the tops of the sweet potato cakes. Peel the parchment from the bottom of one cake layer and place onto a serving plate. Top the cake with a large dollop of frosting and smooth with a butter knife or offset spatula. Top with the second cake layer, then spread the remaining frosting over the top and sides. Decorate the cake as desired, then serve.
Notes
Storage Instructions. Due to the mascarpone cheese frosting, this sweet potato cake must be refrigerated. This cake is best enjoyed the day it’s assembled but will keep for 3 to 5 days in the fridge. Be sure to cover the exposed cake with plastic wrap and store in an airtight container—this ensures that the cake will not dry out or absorb any odors from the fridge. Allow to come to room temperature before serving.
Make-Ahead Instructions:
- Cake layers. Without frosting, the cakes will last about 2 days when wrapped and stored at room temperature. Unfrosted cake layers also freeze well for up to 3 months. Once baked and completely cool, wrap the individual layers in plastic wrap and foil before freezing. Thaw at room temperature before assembling and decorating.
- Sweet potato. The sweet potato purée can be prepared and stored in the fridge up to 5 days in advance.
- Brown butter. The brown butter for the frosting can be made up to 1 week in advance—simply let it come to room temperature before using in the frosting.
This cake is really tasty! The sponge is very moist and the icing is delicious—I don’t normally like frosting, but this one I could eat by the spoonful! Used Greek yogurt instead of sour cream, and it still turned out great.
Yay! So glad you liked the recipe!