Peanut Butter Cake Bars Recipe

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These delicious and addicting bars are made of a layer of cake mix cookie topped with a creamy peanut butter filling, and smothered in a decadent chocolate ganache (or canned chocolate frosting if you’re in a pinch for time)!

Peanut Butter Cake Mix Bars |

No matter how hard I work on a recipe, no matter how creative it is, and no matter how delicious I think it may be… NOTHING ever holds a candle to the response I get from a chocolate and peanut butter peanut butter recipe.

No matter the time of year or season, it seems that chocolate peanut butter mania is an unstoppable force!

Peanut Butter Cake Mix Bars |

Case and point: my Facebook page.

Many blogger’s have struggling Facebook pages these days. Now, I won’t get into the Facebook algorithms and their newest push to monetize fan pages, but in a nutshell: generally speaking, you have to pay Facebook to get fan page posts out to all of your followers. For instance, the Something Swanky Facebook page has nearly 40K likes. But, on a good (GREAT) day, about 2K-3K of those people actually see what I post on my wall, and then about 15 of them share it. (pssst— if you wan to see more from my page, be sure to Like, Comment, and Share a bunch from my page to let Facebook know you want to see more of it!) For those of you who aren’t social media savvy: those aren’t such great stats.

Well. A couple of weeks ago I posted this Reese’s Fudge around 9pm. When I woke up in the morning, over 90,000 people had seen it! My site literally CRASHED from the volume of traffic I was getting from that Facebook post.

I mean. That’s just CRAZY, y’all! I would have NEVER in a million years suspected traffic from a Facebook post would crash my site.

But it appears the power of Chocolate Peanut Butter mania knows no bounds!

Peanut Butter Cake Mix Bars |

Obviously, peanut butter and chocolate are the sweethearts of dessert, and for good reason!

They’re a winning pair, to be sure. But do you know what I love MORE than a great flavor combination? (gasp! There’s something more???)

I LOVE a great texture in a dessert. And I think that’s why I’m all about these Peanut Butter Cake Bars, even more than because they’re PB & Chocolate. There are 3 incredible textures in these bars!

You start out with a chewy cookie-like layer on the bottom (from a cake mix), and then you have a light (but decadent) and creamy layer of peanut butter, and it’s all topped with a thick, fudgy layer of ganache. It’s a trifecta of amazing flavors and textures!!

Peanut Butter Cake Mix Bars |

Peanut Butter Cake Mix Bars |

Peanut Butter Cake Bars


  • 1 Devil's Food Cake mix (ONLY the powder mix, not the other ingredients listed on the box)
  • 1/3 cup butter, melted
  • 1 egg
  • 3/4 cup peanut butter (I prefer crunchy, but it's up to you!)
  • 2 teaspoons vanilla
  • 3 cups powdered sugar
  • 1/2 cup whipping cream
  • optional: 2 tablespoons of milk for thinning if necessary
  • 1 recipe of my Chocolate Ganache, prepared OR 1 can of store-bought chocolate frosting


  1. Preheat oven to 350ºF. Line a 9x13 baking dish with parchment (foil is ok too, but it will stick slightly to the bottom of the bars) and lightly spray with non-stick cooking spray.
  2. In a very large bowl mix together cake mix, melted butter, and egg until a dough forms.
  3. Press dough evenly into the prepared dish. Bake for 12 minutes.
  4. Cool completely in pan.


  1. In a large bowl combine peanut butter and vanilla. Beat with an electric mixer on medium speed for 30 seconds. Add powdered sugar and whipping cream and beat until smooth (with the exception of crunchy peanut butter chunks), scraping bowl occasionally. If mixture is too thick, add 1-2 tbsp of additional milk to thin it.
  2. Spread mixture evenly over the cooled cake mix crust.
  3. Place bars in the refrigerator while preparing the ganache. Or simply heat a can of store-bought chocolate frosting in the microwave for 30 seconds to soften!
  4. Spread the ganache or frosting over the peanut butter layer. Refrigerate for 2-3 hours, or until ganache is set and peanut butter layer is chilled.
  5. Cut into bars and serve!


Recipe slightly modified from Better Homes and Gardens


Don’t miss a bite!

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21 thoughts on “Peanut Butter Cake Bars Recipe”

  1. The last shot with the teeth marks, and the stacks, that is totally a page out of my book and so is PB + chocolate! Girl, love this recipe and these images! Cannot ever go wrong w/ pb + choc and it’s a very nice change from all the mint I see. I have a pb+choc cake for next week. I’m minted out. LOL

  2. Hello! – There is an error in this recipe. Step 5 should include butter or something or else you get a very dry peanut butter and powdered sugar mixture that look like tiny dots. I had to look up the Better Homes and Gardens recipe to figure out what went wrong.


    • Thank you for taking the time to let me know! I subbed the butter BHG uses in their recipe with more peanut butter, but I did leave out the whipping cream! Thank you! And so sorry!

  3. I am making these bars for a play-date tomorrow. I think they will go over great with all the kids. I was just wondering, you recommend using your ganache recipe which lists four different ways to make it. Do you use the second (regular ganache) or the fourth (whipped)? I was thinking of trying the whipped ganache because I thought it would be easier to bite into. I probably can’t go wrong either way though, right?

  4. I was just wondering, what kind of peanut butter did you use? I usually only eat all natural peanut butter but do you recommend not using that in this recipe?

  5. Thank you for getting back to me! So I made them tonight and used Trader Joes organic peanut butter, crunchy. I have not tried them yet (they are cooling in the fridge as I type) but I already know this is going to be my go too recipe if I have to make a dessert for something!! Thank you so much for this recipe it is amazing and so easy!! (I used the ganache #2 and it was perfect, exactly how you described it!)

  6. I made these over the weekend for a bunch of men, hoping they wouldn’t eat them all and save a few but nope, they were gone. Good thing I kept a couple of pieces for me at home ๐Ÿ™‚ We loved them but oh man were they rich mmmm…..! Thanks for the recipe an keep up the great work ๐Ÿ™‚

  7. OMG, Ashton, these bars are stuff your face with all of them good! If I had them, I would totally stuff my face with all of them. I may regret it afterwards, but in the moment, it would be totally worth it. Great recipe, Ashton! ๐Ÿ™‚

  8. I made these for a bake sale. They tasted delicious, but I had a heck of a time cutting them into squares. It was like chiseling them out. The cake base became rather hard.


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