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chocolate cake with fudge filling and white frosting sliced and served on a white plate.

Chocolate Cake with Fudge Filling and White Buttercream

This chocolate cake with fudge filling and white buttercream is incredibly decadent, loaded with chocolate flavor, and the perfect celebration cake for any special event!
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Ingredients

Cake:

  • 1 3/4 cups all-purpose flour
  • 2 cups granulated sugar
  • 3/4 cup unsweetened cocoa powder
  • 1 1/2 teaspoons baking soda
  • 3/4 teaspoon salt
  • 2 eggs
  • 1 cup buttermilk or sub by using a cup of whole milk with a tablespoon of white vinegar and letting it sit 5 minutes until thick
  • 1/2 cup melted butter
  • 1 tablespoon vanilla extract
  • 1 cup hot coffee

Fudge Filling:

  • 1 cup sugar
  • 1/3 cup milk
  • 5 tablespoons butter
  • 1 cup chocolate chips

Buttercream Frosting:

  • 1 cup unsalted butter softened
  • 3 1/2 cups powdered sugar
  • 1-3 teaspoons milk or heavy cream
  • 1 1/2 teaspoons vanilla extract
  • Pinch of salt

Instructions

Prepare the Cake

  • Preheat the oven to 350°F. Grease and flour two 9-inch cake pans, or grease and line with parchment paper circles.
  • In your mixer, add the flour, sugar, cocoa powder, baking soda, and salt and mix until combined. Add the eggs, melted butter, vanilla, and buttermilk, and mix until just combined.
  • Remove the bowl from the mixer and stir the hot coffee into the batter by hand. The batter will be runny. Pour into your cake pans and bake until a toothpick inserted into the center comes out clean with just a few bits of cake stuck to it, about 20-35 minutes.
  • When you remove each cake from the oven, let it cool, run a knife around the edges of the pan, and carefully remove it onto a baking rack. Let cool before frosting.

Making the Fudge Filling

  • Put the first three ingredients into a saucepan over low heat. Bring to a boil, stirring constantly. The sugar should be dissolved. Remove from heat, add chocolate chips, and then whisk them until creamy and cooled.

Make the Frosting

  • In the bowl of a stand mixer, mix the butter and the powdered sugar. Beat until blended, then add salt and mix. Add milk and vanilla and beat until smooth and creamy, about another 3-5 minutes.

Assemble and Decorate

  • Once the cake is cooled, cut each cake in half, then place 1 layer on a plate and spread some fudge filling over the layer. Then place another layer on top and frost with fudge filling, place third layer onto and frost, and then place the last layer on top.