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Marble Cake

Marble cake features two buttery, rich layers of fluffy white and chocolate swirled cake topped with rich chocolate frosting.
Prep Time 25 minutes
Cook Time 40 minutes
Chill Time 1 hour
Total Time 2 hours 5 minutes
Course Dessert
Cuisine American
Servings 12

Ingredients
  

White Cake

  • 1 box white cake mix or yellow cake mix
  • ½ cup salted butter softened
  • 3 large eggs
  • ¼ cup sour cream
  • 1 cup milk or buttermilk
  • 1 teaspoon vanilla extract

Chocolate Cake

  • 1 box chocolate cake mix
  • ½ cup salted butter softened
  • 3 large eggs
  • ¼ cup sour cream
  • 1 cup milk or buttermilk
  • 1 teaspoon vanilla extract

Frosting

  • 1 cup salted butter softened
  • ½ cup unsweetened cocoa powder
  • ½ cup hot water or heated heavy cream
  • 2 cups powdered sugar
  • 4 ounces German chocolate or semi-sweet baking bar melted and cooled

Instructions
 

  • Preheat the oven to 325°F. Spray two 9-inch round cake pans with non-stick cooking spray or use the wrappers from the butter to grease them thoroughly.
  • In one mixing bowl, combine the white cake ingredients: cake mix, butter, eggs, sour cream, buttermilk, and vanilla extract. Beat on low speed for 1 minute and then on medium-high speed for two additional minutes. Set aside.
  • In a second mixing bowl, combine the chocolate cake ingredients: chocolate cake mix, butter, eggs, sour cream, buttermilk, and vanilla extract. Beat on low speed for 1 minute and then on medium-high speed for two additional minutes.
  • Using an ice cream scoop or large spoon, pile dollops of cake batter into the pans, rotating between the white and chocolate cake mixes. Fill the pans about ⅔ of the way full to prevent overflowing. You may not use all of the batter.
  • Use a knife to cut through the batter and swirl the two colors. Do not over swirl, which can result in the colors blending.
  • Bake for about 40 minutes or until a toothpick inserted into the cakes comes out with just a few crumbs. The pans are going to be more full than with a single cake mix, so the cook time will likely be 5 to 10 minutes longer than indicated on the box of cake mix.
  • Cool the cakes for 10 to 15 minutes and then remove the cakes from the pans and let them cool completely on a cooling rack.
  • Meanwhile, prepare the frosting. Chop the German chocolate baking bar into small pieces. Use a double boiler or 30-second increments in the microwave to melt the chocolate. Stir until fully melted and set aside to cool.
  • Use a whisk to stir together the cocoa powder and hot water (or hot cream) until smooth and shiny.
  • In a large mixing bowl, beat together the softened butter, cooled German chocolate, cocoa powder mixture, and powdered sugar. Beat until fully combined and fluffy.
  • Level the tops of the cakes (and any lip from overfilled cake pans) with a serrated knife.
  • Frost the bottom cake layer with about ½ cup of chocolate frosting.
  • Stack the second cake layer on top of the first, top side down.
  • Frost the top and sides of the cake with the remaining frosting.

Notes

PRO TIP: I filled my pans quite full (¾ of the way full) to use up all the batter. I baked the cakes with a sheet pan on the shelf underneath in the oven to catch any spills. The cakes puffed over the rim. If you have deeper 9-inch cake pans, you can use those. I like the extra height on the cakes by filling the pans really full. You can just trim any overage with a bread knife before frosting.
PRO TIP: The marble effect comes from swirling the two cake colors into each other. There isn’t a specific pattern or movement; just let your knife flow all the way down to the bottom of the pan and swirl a few times in curved strokes throughout the batter.
PRO TIP: Freeze cake layers before frosting to make them firmer and easier to assemble and frost. Wrap with plastic wrap once cooled completely and then place in the freezer for 1 hour or up to 1 week. No need to defrost before assembling and frosting the cake.
PRO TIP: The frosting can be chilled in the refrigerator if it is too soft or if you wish to prepare it in advance. Give it another quick beat with a hand or stand mixer before using it to frost the cake. The frosting is not shelf-stable - meaning that the cake should be kept chilled until serving and for storage.