Peanut Butter Mississippi Mud Brownies #Choctoberfest

by Erin

Ever had a Mississippi Mud Pie? Well now it comes in brownie form and I may have even added some peanut butter. As if it needed to be richer.

Peanut Butter Mississippi Mud Brownies 5

While Ohio State may not have a game today, it’s still Saturday and I’m not gonna let a bye week stop my from enjoying yet another #PBChocSat. Besides we are having people over to watch the Penn State vs Michigan game tonight! Or as I like to call it, cheering for Michigan to lose and therefore cheering for Bob’s team to win. It’s the one game a year we band together in our hatred for that team up North.

Peanut Butter Mississippi Mud Brownies 1

In addition to my usual peanut butter and chocolate Saturday creations, today marks the final day of #Choctoberfest, a week-long celebration of all things chocolate. What better way to end the celebration than with an incredible brownie? Namely a rich dense brownie topped with peanut butter, marshmallow, pecans, and a chocolate ganache. Apparently such a thing is called a Mississippi mud brownie.

Peanut Butter Mississippi Mud Brownies 2

Just like the chess pie, the origin of the mud pie (from which these brownies are inspired) remains to be elusive and while we may never know the story behind the pie, I think everyone can agree it must have some correlation to the dark, goopy mud found along the Mississippi River. I lived in Memphis right along that very river and I can attest to it.

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To make these brownies a bit more goopy I added peanut butter because when is that ever not a good idea? As usual these bad boys turned out so good I had to promptly bestow them upon others so I will be making sure every last one gets devoured at our party today. As if that’s going to be difficult to accomplish.

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Think there’s no such thing as too much chocolate? Remember to check the link up at the end of this post for all the final recipes for the week and don’t forget to enter the chocolate lover’s giveaway HERE!

Peanut Butter Mississippi Mud Brownies 6

Two years ago: Pumpkin Corn Spoon Bread

Three years ago: Slow Cooker Vegetarian Pumpkin Chili

Four years ago: Chocolate Pumpkin Cupcakes with Cinnamon Buttercream

Six years ago: Stuffed Flank Steak with Potato Cakes and Amaretto Chocolate Cheesecake


Makes 16 bars


8 oz. semisweet chocolate chips

1/2 cup unsalted butter, room temperature

1/2 cup Dixie Crystals granulated pure cane sugar

1/4 cup Imperial Sugar packed light brown pure cane sugar

3 eggs, room temperature

1 tsp vanilla extract

1/2 cup + 2 Tbsp all-purpose flour

2 Tbsp Rodelle Dutch processed baking cocoa powder

1 tsp salt


1/2 cup crunchy peanut butter

1-1/2 tsp vegetable oil

2 cups mini marshmallows

1/2 cup chopped, toasted pecans


1/4 cup (4 Tbsp) unsalted butter

2 Tbsp Rodelle Dutch processed baking cocoa powder

1/4 cup + 2 Tbsp milk

2 cups Imperial Sugar pure cane powdered sugar

1/8 tsp salt

1/4 tsp vanilla extract


  1. Preheat the oven to 350°F. Line an 8×8 or 9×9-inch baking dish with foil or parchment paper, leaving an overhang on each side. Set aside.
  2. Place a medium heat-safe mixing bowl over a saucepan of simmering water. Add chocolate and butter to the bowl. Stir until melted and smooth. Remove from heat.
  3. In a large mixing bowl, whisk together sugars, eggs, and vanilla. Slowly whisk in the chocolate mixture until thoroughly combined. Gently fold in flour, cocoa, and salt until just combined. Pour into prepared baking dish and bake for 35-40 minutes or until a tooth pick comes out with a few moist crumbs. Remove from oven but keep oven on.
  4. When brownie layer is done baking, combine peanut butter and oil in a microwave safe bowl or measuring cup and microwave on high for 20 seconds to soften. Pour over hot brownie and sprinkle with marshmallows. Return to oven to bake for 3 more minutes, or until the marshmallows puff. Sprinkle with toasted pecans.
  5. To make frosting, in small saucepan, melt butter over medium heat. When butter is melted, add the cocoa powder and 1/4 cup of the milk and heat until the mixture begins to boil. Remove from the heat and combine with powdered sugar and salt in a separate bowl and beat on high speed with an electric mixer until smooth and glossy. If frosting is not pourable at this point, add remaining 2 tbsp of milk (I didn’t have to do this). Lastly, beat in vanilla, then pour evenly over brownies.
  6. Let cool completely in refrigerator for 1-2 hours. Cut into squares and enjoy!

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Source: Adapted from my Pumpkin Spice Peanut Butter Cookie Dough Brownies and Greens & Chocolate.

Disclosure: I was provided with complimentary product from our generous sponsors of this event, Imperial Sugar and Rodelle. All thoughts and opinions remain my own.

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Chocolate Peanut Butter Cookies December 6, 2020 - 3:39 pm

[…] Peanut Butter Mississippi Mud Brownies by The Spiffy Cookie […]

cakespy October 24, 2017 - 6:51 am

Oh good god. This is like poetry, but even better because they’re edible.

spiffycookie October 24, 2017 - 8:03 pm

Edible poetry is my favorite.

Karen October 22, 2017 - 1:43 am

Thank goodness, someone is paying attention!

Kayla October 21, 2017 - 5:41 pm

Adding peanut butter is ALWAYS a good thing. I’ve never thought about including marshmallow in on the chocolate/PB combo.. sounds delicious!

spiffycookie October 23, 2017 - 8:44 am

It’s so good!!

Stella October 21, 2017 - 6:51 am

These look amazing! Do you think almond butter would work? My son has a peanut allergy. Also, GO BLUE! ????

spiffycookie October 23, 2017 - 8:10 am

I don’t see why almond butter wouldn’t work, just a different flavor. And I will ignore your last comment :-P.


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