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Fudge Frosted Peanut Butter Cake

Fudge Frosted Peanut Butter Cake Recipe l

I realized the other day that I have never made a plain peanut butter cake. Sure I’ve made peanut butter banana cake, I’ve made peanut butter swirled chocolate cake, etc. but no plain peanut butter cake.

That had to change. Since peanut butter and chocolate is one of my favorite combinations. It only seemed right to make a chocolate frosting to go with it!

Fudge Frosted Peanut Butter Cake Recipe l

The base of this fudge frosted peanut butter cake has a light peanut butter flavor, not too intense or overpowering.

I was tempted to add more peanut butter (because peanut butter is good!), but I wanted to keep the texture from getting too dense.

It was just the right amount of peanut butter to give it flavor while keeping the cake tender.

Fudge Frosted Peanut Butter Cake Recipe l

To top this peanut butter cake I went with an old standby. I use this same frosting for my family’s chocolate wacky cake, and it’s always been a favorite. The frosting tastes just like chocolate fudge.

It’s thick, rich, and decadent. Just the right frosting for a peanut butter cake! (And just the right frosting to eat straight from the bowl. No one needs to know!)

Fudge Frosted Peanut Butter Cake Recipe l

Fudge Frosted Peanut Butter Cake

Yield: 24 pieces of cake


For the Cake

  • 1/3 C creamy peanut butter
  • 1 C water
  • 1/2 C butter
  • 1 C sugar
  • 1 C brown sugar
  • 2 C flour
  • 1/2 tsp salt
  • 1 tsp baking soda
  • 2 eggs
  • 1/2 C milk
  • 1 tsp vanilla extract

For the Frosting

  • 1 1/2 C sugar
  • 3 tbsp unsweetened baking cocoa
  • 1/3 C milk
  • 1/3 C butter
  • 1 tsp vanilla extract


  1. Preheat oven to 375. Lightly spray a 9x13 inch baking dish with non-stick cooking spray.
  2. In a medium saucepan, melt together peanut butter, water, and butter over medium heat. Stir to prevent scorching. Remove from heat.
  3. In a large bowl, whisk together sugars, flour, salt, and baking soda. Stir in peanut butter mixture. Add eggs, milk, and vanilla extract and beat until well-combined.
  4. Pour batter into prepared baking dish. Bake for 25-30 minutes or until toothpick inserted in the center comes out clean.
  5. Remove to a wire rack to cool.
  6. In a medium saucepan, stir together sugar and baking cocoa. Add in milk and butter. Bring to a boil over medium heat. Stir constantly to prevent scorching. Boil for 5 minutes. Remove from heat and add vanilla. Beat with a sturdy spoon until glossy and thickens. This will take a few minutes.
  7. Spread over cooled cake. Frosting hardens as it cools, so work quickly.
  8. Cut into pieces and serve.

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Did you make this recipe?

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The base of the cake is adapted from The Girl Who Ate Everything.


Tuesday 9th of December 2014

This. Cake. Is. AWESOME! EASILY one of the top 3 best cakes I've ever had. And the frosting is absolutely indulgent! But I didn't care for this frosting on this cake. The chocolate fudge overpowered the peanut butter flavor. Next time I'll try the cake with a regular chocolate buttercream. And I'm going to try the fudge frosting on a regular yellow/butter cake. But both of these recipes will remain in my arsenal forever! Thank you for sharing! :)


Wednesday 2nd of July 2014

I was making the frosting for this cake, and it looked fine until I added in the vanilla. When I added the vanilla, and stirred it in, the frosting immediately turned into a powder (looked like I had a saucepan of cocoa powder). The frosting only sat long enough for me to measure out the vanilla. Does anyone have any idea as to what I may have done wrong? Thanks.

Jessica@A Kitchen Addiction

Wednesday 2nd of July 2014

I am not entirely certain what could have caused this. The only thing I can think of is that the cocoa powder wasn't completely stirred in so a pocket of it was uncovered when you stirred in the vanilla. . . I will have to look into this. I'm sorry it didn't work for you!


Wednesday 2nd of July 2014

i need to try this!!! can anyone help with UK conversions please? (and is C sugar-confectioners or castor?) Many thanks x

Jessica@A Kitchen Addiction

Wednesday 2nd of July 2014

C stands for cup. So it's just plain white sugar. Allrecipes seems to have good charts for conversions: Hope this helps!


Friday 21st of March 2014

it looks yummy!

Cate @ Chez CateyLou

Friday 21st of March 2014

mmmm, I have never made a plain peanut butter cake either! Definitely need to try this - it looks sooo good. Chocolate PB is my husband and my favorite combo!

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