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The Best Sweet Potato Cake with Italian Buttercream Meringue Frosting

Prep Time1 hr
Cook Time25 mins
Servings: 8
Cost: 8

Ingredients

For the Cake

  • 2 1/4 c cake flour
  • 1 tsp baking soda
  • 2 tsp baking powder
  • 1/8 tsp salt
  • 1 1/2 tsp ground cinnamon
  • 1/2 tsp nutmeg
  • 1/4 tsp ground ginger
  • 1 1/2 sticks butter room temperature
  • 1 cup sweet potato baked, skinned, mashed
  • 3/4 c buttermilk
  • 1 tsp vanilla extract
  • 2 eggs room temperature

Italian Buttercream Meringue Frosting

  • 5 egg whites room temperature
  • 1 1/2 c granulated sugar
  • 1/2 tsp cream of tartar
  • 1 c water
  • 1 1/2 tsp vanilla extract
  • 1/2 c powdered sugar if needed (for added sweetness)
  • 4 sticks butter 4 sticks = 1 lb

Instructions

To Make the Cake

  • Heat oven to 350 degrees F.
  • Butter and flour two 9" cake pans. Line with parchment paper. Tip: butter both sides of parchment paper and flour the top. Set aside.
  • In medium mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, ginger and salt. Set aside.
  • Into another mixing bowl, beat sweet potato until smooth. Note: Mashing the potato will leave it too chunky. I used an immersion blender, but you can use a food processor, blender or hand mixer.
  • Stir buttermilk and vanilla extract into the sweet potato; set aside.
  • In the bowl of a stand mixer, or with a hand mixer, beat together the butter and sugar until pale yellow and fluffy, about 3-4 minutes.
  • Add eggs, one at a time. Scrape down sides and beat another 10 seconds. Slowly beat in sweet potato mixture until smooth, about a minute.
  • To butter mixture, add the flour mixture and beat until well-blended.
  • Pour evenly into cake pans and bake for about 25 minutes, until toothpick comes out dry when inserted in the center, Remove cake from oven.
  • After 5 minutes, remove cakes from pan and let cool completely before frosting.

For the Italian Buttercream

  • Before beating the eggs, make sure the bowl, the whisk attachment, spatula, etc,. are all very clean and wiped down with lemon juice or white vinegar.
  • To bowl of stand mixer, add egg whites, cream of tartar, salt and beat with whisk attachment until foamy. On medium speed, slowly sprinkle in 1/4 cup of the sugar, and then beat on medium high until soft peaks form.
  • Add 1/4 cup water and 1 cup of the sugar to small sauce pan and heat until bubbling and reaches 240 degrees F. It's best to use a candy thermometer to make sure it's precise.
  • On slow speed, slowly drizzle the hot sugar water into the egg mixture. Once the liquid has been added, increase the speed to medium high and beat until stiff picks form and the mixture has cooled.
  • Switch to paddle attachment and on medium speed start adding the butter a couple tablespoons at a time. The texture will change, but continue to beat until the mixture until desired consistence. This could take about 10 minutes.
  • Taste the frosting, and if you'd like it sweeter, add another 1/2 cup or more of powdered sugar while continuing to beat.

Make the Layer Cake

  • Spread and one-inch layer of frosting on the first cake and then top with the second cake. Press down to make sure it's even. Frost cake to cover as desired. To decorate, add frosting to piping bag with a large tip.