Peanut Butter Brownie Cake

Peanut Butter Brownie Cake ~ this little dessert is a cross between a brownie and a blondie, with a good dose of peanut butter frosting thrown in for good measure!

I had two (not one, but two) baking fails yesterday. This peanut butter brownie was supposed to be a peanut butter blondie. Don’t ask.

But here’s the interesting thing about kitchen failures. They sometimes work out well.

Peanut Butter Brownie Cake cut in squares

And from what I can tell it’s a common thing for a blondie to want to experiment with a different look now and then. A couple of weeks before my wedding I dyed my blonde hair black. It was supposed to be a ‘wash out‘ color, but of course it didn’t ‘wash out‘, and in all my wedding photos I’m brunette. That provided an endless source of hilarity for my daughters over the years.

If there’s one thing that I hope comes across in this blog it’s an open mind towards food. I’m pretty much of an equal opportunity eater. So while I was craving a blondie, with chunks of dark chocolate chips throughout, I got a delicious brownie, and that’s ok with me. And even though I usually prefer to cook with butter over shortening, I’m always up for an experiment when it comes to food. This brownie cake contains Crisco butter flavored shortening in both the cake and the frosting, and while it does yield a slightly different result than butter or oil, I like it in this cake.

The frosting is especially good, it has a creamy texture with a little hit of salt. The brownie is moist and dense. I think this is a keeper. And if you love the nutty chocolate combo in this recipe, you’ll probably also like my Easy Cashew Tiger Butter, and my Dark Chocolate Hazelnut Fudge.

My rule of thumb for measuring the success of a recipe is to ask myself if I would make it again. Me to Self:  Would you make this again?  Self:  Yes!

Would I dye my hair black again? No!

3.6 from 5 votes

Peanut Butter Brownie Cake Squares

Peanut Butter Brownie Cake ~ this little dessert is a cross between a brownie and a blondie, with a good dose of peanut butter frosting thrown in for good measure!
Course Dessert
Cuisine American
Prep Time 15 minutes
Cook Time 20 minutes
Yield 9 servings
Author Sue Moran


  • 2 cups all purpose flour
  • 1 1/2 tsp baking powder
  • 1 tsp salt
  • 1 cup shortening
  • 1 cup peanut butter
  • 1 lb brown sugar about 3 1/3 packed cups
  • 3 eggs
  • 1 tsp vanilla extract
  • 10 oz bag of Nestle Dark Chocolate Chips about 1 1/2 cups


  • 1 pound confectioner's sugar 1/2 of a 2 pound bag
  • 1/2 cup peanut butter
  • 1/2 cup shortening
  • 1 tsp salt
  • 1 tsp vanilla
  • about 1/3 - 1/2 cup hot water


  • Set oven to 350F
  • In a small bowl whisk together the flour, baking powder and salt. Set aside.
  • In a large bowl beat the shortening, peanut butter and sugar together for a couple of minutes. Beat in the eggs and vanilla for another couple of minutes.
  • Heat the chocolate in the microwave just until melted. Heat for 30 seconds, then stir and heat at 15 second intervals stirring to melt fully. Don't over heat. Cool slightly.
  • Add the cooled chocolate to the bowl and beat until blended.
  • Fold in the dry mixture, just until combined. Spread into a 9x12 inch pan and bake for about 20 minutes, until a toothpick comes out clean (but it will be damp) Don't over bake, as this is a brownie like cake.
  • To make the frosting: Beat the sugar, peanut butter, shortening, salt and vanilla together, adding enough hot water to form a smooth, spreadable frosting. You can adjust by adding more sugar or more water as needed. Don't have it too thick or it won't spread nicely.
  • Spread on the still warm cake, and let cool before slicing, if you can possibly wait.

Cook's notes

  • If you still prefer blondies, you can make it the way I intended to...don't melt the chocolate chips, just fold them into the batter.
The nutritional information for recipes on this site is provided as a courtesy and although tries to provide accurate nutritional information, these figures are only estimates.
Peanut Butter Brownie Cake pin

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    Please rate this recipe!

  • Reply
    May 10, 2017 at 10:00 am

    5 stars
    Oh, Sue, you shouldn’t have. What am I saying! ! Thank you so many times : i.e. Thank you, Thank you,Thank you.
    A big plus also are the baking temperature. I have found very few delicious recipes that call for a 350 degree oven. That maxes out my little oven. No room for a regular oven. I have finally found an upside to being a cancer patient. I can eat anything I want without worrying about calories. lol Your recipes are wonderful. Please keep ’em coming.

    • Reply
      May 10, 2017 at 10:05 am

      I’m so glad you like these Cheryl ~ and it sounds like you have an amazing attitude and that you’re fighting that cancer with all you’ve got ~ you deserve a little PB and chocolate reward 🙂

  • Reply
    August 16, 2012 at 9:37 pm

    disaster averted, hooray! these look really amazing, sue. that peanut butter frosting is welcome to top anything, as far as i’m concerned.

  • Reply
    Hillary Miller
    August 14, 2012 at 3:24 am

    Hi Sue,
    Based on your delicious Peanut Butter Brownie Cake Squares photos, we’d like to invite you to submit your food photos on a food photography site called so our readers can enjoy your creations.
    It is absolutely free and fun to make others hungry!
    Thanks 🙂

  • Reply
    August 13, 2012 at 6:57 pm

    Why does your kitchen disaster look so much better than all mine put together? Ok you didn’t say it was a disaster – I’m referring to my kitchen disasters which are usually not edible, much less blog-able! Very nice idea. Chocolate and peanut butter are my favorite couple in the whole world!

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