Peanut Butter Cake


Peanut Butter Cake

  • 2 cups all-purpose flour or cake flour
  • 2 cups granulated sugar
  • 1 teaspoon baking soda
  • ¼ teaspoon salt
  • 3/4 cup water
  • 10 tablespoons unsalted butter
  • ¾ cup creamy peanut butter
  • 2 large eggs room termperature
  • 3/4 cup buttermilk room temperature
  • 1 1/2 teaspoons vanilla extract

Peanut Butter Frosting

  • 12 tablespoons unsalted butter
  • 1 cup creamy peanut butter
  • 2 cups powdered sugar
  • ¼ cup milk
  • 1 teaspoon vanilla extract
  • ¼ teaspoon salt


  • Preheat the oven to 350 degrees.  Grease and flour a 15×10-inch jelly roll pan.
  • In a large bowl, whisk together flour, sugar, baking soda, and salt.
  • Combine water and butter in a large saucepan and heat until the butter melts.  Make sure the saucepan is large enough to mix a cake in. Whisk in the peanut butter until smooth. Remove from the heat and let cool for 10-15 minutes stirring several times.
  • Stir the flour mixture into the peanut butter mixture just enough to get it started.  Add the eggs, buttermilk, and vanilla.  Stir just enough to combine.  Pour into the prepared pan and bake for 24-28 minutes or until a toothpick inserted in the center comes out clean.  Remove the cake to a wire rack and fully cool before preparing the frosting.
  • Using a stand mixer with the paddle attachment, cream the butter and peanut butter until smooth and creamy. Add the powdered sugar in 1/2 cup increments alternating with 1 tablespoon of milk while continuing to beat on medium speed. Scrape down the bowl and beater as needed. Beat in the vanilla and salt.  Continue beating for about 3-4 minutes or until the frosting is smooth and fluffy.
  • Frost the fully cooled cake.


  • You can also bake this cake in a 9×13 inch pan, but baking time will increase to about 35-40 minutes. Or bake in a half-sheet pan, but baking time will decrease by a few minutes, 
  • Let the butter, peanut butter, and water mixture cool for at least 10 minutes before proceeding with the rest of the cake so your eggs do not start cooking in the hot mixture.
  • For the best texture in the cake and frosting, use the old-fashioned peanut butter that does not separate.
  • Do not overbake the cake.  It is done when a toothpick inserted in the center comes out clean.
  • With the amount of milk in this frosting, it is best to refrigerate the frosted cake.  Cover it well and refrigerate for up to 4 days.
  • When baked in a jelly roll pan, this cake feeds about 20. So, it is the perfect dessert for potlucks and family reunions.
  • Try adding mini chocolate chips to the cake batter or add 2 tablespoons of good quality unsweetened cocoa powder to the frosting.

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