These Mississippi Mud Brownies are decadent and delicious! A moist brownie layered with chocolate chips, topped with melted crunchy peanut butter, marshmallows, sprinkled with toasted pecans and lacquered with a thin layer of frosting.

Mississippi Mud Brownies l

I am totally smitten with these Mississippi Mud Brownies.

A fudge brownie layered with chocolate chips, melty peanut butter, marshmallow and a decadent chocolate pecan frosting.What’s not to love?

Mississippi Mud Brownies l

To Make These Mississippi Mud Brownies You Will Need:

for the brownies:

  • unbleached all-purpose flour
  • unsweetened cocoa powder
  • salt
  • unsalted butter (room temperature)
  • granulated sugar
  • pure vanilla extract
  • eggs
  • semi-sweet chocolate chips
  • crunchy peanut butter
  • canola oil
  • mini marshmallows
  • chopped toasted pecans

for the frosting:

  • powdered sugar
  • kosher salt
  • unsalted butter
  • unsweetened cocoa powder
  • milk
  • pure vanilla extract

These brownies require a few basic pantry ingredients, and they take less than 30 minutes to prepare! I chopped the toasted pecans ahead of time to quicken the process a bit.

Mississippi Mud Brownies l

Make The Brownies:

Start off by measuring 3/4 cups unbleached all-purpose flour, 2 tablespoons unsweetened cocoa powder and 1/2 teaspoon kosher salt. Add them into a small bowl.

Mississippi Mud Brownies l

Stir to combine and set aside.

Mississippi Mud Brownies l

Cream 1 stick of butter along with 1 cup of sugar until light and fluffy.

Mississippi Mud Brownies l

Next add in 3/4 teaspoons vanilla extract.

Mississippi Mud Brownies l

Add 2 large eggs, one at a time and blend well after each addition until both are incorporated.

Mississippi Mud Brownies l

Next, add the dry ingredients in with the sugar/butter mixture and stir to combine.

Mississippi Mud Brownies l

Spread the brownie mixture into the bottom of a lined 8×8 square pan.

Mississippi Mud Brownies l

Sprinkle with 3/4 cups chocolate chips and pop into a 350ºF oven for about 20-22 minutes.

Mississippi Mud Brownies l

Once the brownies have baked, here comes the really fun part.

Mississippi Mud Brownies l

Start by mixing 1 and 1/2 teaspoons flavorless oil in with 1/2 cup warmed crunchy peanut butter.

Mississippi Mud Brownies l

Then evenly pour the peanut butter all over the warm brownies.

Mississippi Mud Brownies l

Sprinkle 2 cups of marshmallows over the peanut butter. Bake in the oven for 3 minutes, just to puff up the marshmallows.

Mississippi Mud Brownies l

Top with 1/2 cup chopped toasted pecans and set aside and let cool. Now it’s time to make the frosting!

Mississippi Mud Brownies l

Prepare the Frosting:

In a small pan, melt 4 tablespoons of unsalted butter. Next add in 2 tablespoons cocoa. Stir and gradually pour in 1/4 cup milk. Heat the chocolate mixture until just about boiling, remove from the heat and add ¼ teaspoons vanilla extract. You could also add the vanilla to the frosting once it’s been mixed.

Mississippi Mud Brownies l

In a mixing bowl that contains 2 cups powdered sugar and 1/8 teaspoon salt, pour in the warm chocolate mixture while the mixer is on low speed.

Mississippi Mud Brownies l

Scraping down the sides as you go, mix until the powdered sugar is absorbed into the chocolate. If the frosting looks too thick, add 1 to 2 tablespoons of milk to thin it out.

Mississippi Mud Brownies l

Pour over the pecans and marshmallows.

Mississippi Mud Brownies l
After I poured the icing over top, I realized my frosting must have cooled down too much because the icing didn’t melt into the crevices of the pecans and marshmallow. So I just spread the frosting out evenly. Once cooled enough, I placed the pan into the fridge for an hour or two.

Mississippi Mud Brownies l

It wasn’t until I removed the Mississippi Mud Brownies and pulled back the parchment paper did I realize what I was in for. These bars contain everything that I love in life. And it was almost too pretty to eat.


Mississippi Mud Brownies l
This is exactly what one needs to get over the cold weather and post holiday blues. Just be sure to pour yourself a giant glass of milk, because these brownies are rich and will definitely make you thirsty.

These Mississippi Mud Brownies were so much fun to make and definitely the most decadent brownie I have ever had the pleasure to taste!

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Yield: 9 servings

Mississippi Mud Brownies

You'll be smitten with these Mississippi Mud Brownies. A moist brownie layered with chocolate chips, topped with melted crunchy peanut butter, marshmallows, sprinkled with toasted pecans and lacquered with a thin layer of frosting.



  • 3/4 cups unbleached all-purpose flour
  • 2 tablespoons unsweetened cocoa powder
  • 1/2 teaspoons kosher salt
  • 1/2 cup unsalted butter, at room temperature
  • 1 cup granulated sugar
  • 2 large eggs
  • 3/4 cup semi-sweet chocolate chips
  • 1/2 cup crunchy peanut butter


  • teaspoons grapeseed oil, or canola
  • 2 cups mini marshmallows
  • 1/2 cup pecans, chopped and toasted
  • 2 cups powdered sugar
  • 1/8 teaspoons kosher salt
  • 4 tablespoons unsalted butter
  • 2 tablespoons unsweetened cocoa powder
  • 6 tablespoons milk
  • 1/4 teaspoons pure vanilla extract



  • Preheat oven to 350°.
  • Line an 8×8″ square baking pan with parchment paper or foil. If using foil, spray it with cooking spray.
  • In medium bowl, combine flour, cocoa powder, and salt. Set aside.
  • In large mixing bowl, beat together butter, sugar, and until creamy. Add the eggs one at a time.
  • Stir dry ingredients into batter.
  • Pour batter into prepared pan and spread evenly. Sprinkle with chocolate chips. Bake in preheated oven for 22-25 minutes.
  • 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 this warm mixture over hot brownie and spread. Sprinkle the peanut butter covered brownies with marshmallows. Return to oven to bake for 3 more minutes, or until the marshmallows puff.
  • Remove from oven and sprinkle puffed marshmallows with toasted pecans.


  • Combine confectioners sugar and salt.
  • In small saucepan, melt butter over medium heat. When butter is melted, add the cocoa powder and milk and heat until the mixture begins to boil.
  • Pour this mixture into confectioners sugar/salt mixture and beat on high speed with an electric mixer until smooth and glossy. If frosting is not pourable at this point, add remaining milk.
  • Lastly, beat in vanilla, then pour evenly over puffed marshmallows and pecans.
  • Let cool completely in refrigerator for 1-2 hours. Cut into squares and enjoy!
Serving: 1g, Calories: 641kcal, Carbohydrates: 79g, Protein: 8g, Fat: 35g, Saturated Fat: 15g, Polyunsaturated Fat: 5g, Monounsaturated Fat: 12g, Trans Fat: 1g, Cholesterol: 84mg, Sodium: 265mg, Potassium: 294mg, Fiber: 4g, Sugar: 62g, Vitamin A: 558IU, Vitamin C: 1mg, Calcium: 47mg, Iron: 2mg

Recipe adapted from Greens and Chocolate.