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slice of butterfinger cake on a plate next to two forks with the rest of the cake in the background

Butterfinger Cake

Butterfinger cake combines peanut butter cake layers, Butterfinger filling, and chocolate peanut butter frosting to make a delicious chocolate-y and peanut butter-y cake!

Course Dessert
Cuisine American
Prep Time 40 minutes
Cook Time 30 minutes
Cooling time 3 hours
Total Time 4 hours 10 minutes
Servings 10
Author Kelsie

Ingredients

Peanut butter cake layers

  • 1 cup water
  • 1/2 cup unsalted butter
  • 1/2 cup vegetable oil
  • 1/2 cup creamy peanut butter don’t use natural
  • 2 cups all-purpose flour
  • 2 cups granulated sugar
  • 1 teaspoon baking soda
  • 3/4 teaspoon salt
  • 1/2 cup full fat sour cream
  • 3 tablespoons whole milk
  • 2 large eggs
  • 1 teaspoon vanilla extract

Butterfinger filling

  • 1/2 cup unsalted butter at room temperature
  • 3 cups powdered sugar
  • 3 tablespoons milk or heavy cream
  • 1/4 teaspoon salt
  • 3/4 cup finely chopped Butterfingers from about 4 to 4 1/2 ounces of candy

Chocolate peanut butter frosting

  • 3/4 cup unsalted butter at room temperature
  • 1/4 cup creamy peanut butter don’t use natural
  • 1/2 cup cocoa powder
  • 1/4 teaspoons salt
  • 5 to 8 tablespoons milk or cream
  • 4 to 4 1/2 cups powdered sugar
  • Additional chopped butterfingers for garnish

Instructions

Peanut butter cake layers

  1. Preheat the oven to 350 degrees. Spray 3 8-inch round cake pans with cooking spray and line the bottom of the pans with parchment. Spray the parchment with cooking spray and set pans aside.
  2. Combine the water, butter, vegetable oil, and peanut butter together in a medium saucepan set over medium heat. Cook, stirring often, until peanut butter and butter are melted and mixture is smooth. Remove from the heat and let cool while you continue with the cake.
  3. Combine the flour, sugar, baking soda, and salt together in a large mixing bowl and beat with an electric mixer to combine. Add the sour cream, milk, eggs, and vanilla and beat on low speed until combined.
  4. Add the cooled peanut butter mixture and beat on low until batter is smooth, stopping mixer to scrape the sides and bottom of the bowl several times. Batter will be fairly thin.
  5. Divide batter evenly between the prepared pans and bake for 29 to 35 minutes, until a cake tester inserted into the center of the pans comes out clean.
  6. Cool cake layers in the pans for 30 minutes, then carefully invert onto a wire rack to cool completely before filling and frosting.

Butterfinger filling

  1. Combine the butter, powdered sugar, milk, and salt in a medium mixing bowl and beat with an electric mixer on low speed until combined. Increase the speed to medium and beat until smooth. Use a rubber spatula to fold in the chopped Butterfingers.

Chocolate peanut butter frosting

  1. Beat the butter and peanut butter in a large mixing bowl with an electric mixer until very smooth. Add the cocoa powder and salt and beat to combine.
  2. Add 5 tablespoons of the milk and 4 cups of the powdered sugar and beat on low to combine, then increase speed to medium and beat until smooth. Add more milk if frosting is too thick and more powdered sugar if frosting is too thin.
  3. Assembly:
  4. Place one layer on a cake stand or cardboard cake circle.
  5. Transfer about a 1/2 cup of frosting to a pastry bag fitted with a large round tip and pipe a circle of frosting around the perimeter of the cake. Use an offset spatula to spread half of the filling into an even layer inside the circle of frosting.
  6. Top with another cake layer and repeat the filling process. Top with the remaining cake layer. Frost your cake and decorate with additional chopped butterfingers if desired. Serve.

Recipe Notes

  • Don't skip lining your pans with parchment! Even with cooking spray, the cake layers will stick!
  • If you don’t have pastry bags and tips, you can just spread the filling over the cake layer without going all the way to the edge. This will prevent the filling from leaking out into the final coat of frosting.