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Mississippi Mud Brownies

Mississippi Mud Brownies are my dream come true – a thick and fudgy brownie covered with marshmallows and chocolate icing. No boxed brownie mix here. It’s much better from scratch!

Mississippi Mud Brownies

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Mississippi Mud Brownies

My favorite food is marshmallows so it’s no surprise that I love these Mississippi Mud Brownies.

The brownies are unbelievably fudgy and the marshmallowy chocolate frosting totally has my heart.

Key to Success #1 – Use Melted Butter in the Brownies

You don’t need to get out your mixer for these brownies.

You can whip these up using just one microwave-safe bowl and a sturdy spoon.

Start off by melting your butter in the microwave then stir in the unsweetened cocoa powder.

Once it’s smooth, stir in the sugar then add the beaten eggs and vanilla.

Gently stir in the dry ingredients.

Note that this brownie recipe does not call for baking powder or baking soda. This allows the brownies to bake up thick and fudgy and not fluffy and cake-like.

Mississippi Mud Brownies

Key to Success #2 – Watch the Cook Time Carefully

Since these brownies are so fudgy, you’ll have to watch them carefully in the oven so that they don’t over-bake and turn hard around the edges.

Test the brownies by inserting a toothpick into the center of the brownies.

If the toothpick is wet, cook the brownies for another 5 minutes.

If the toothpick has a few moist crumbs on it, your brownies are ready.

Mississippi Mud Brownies

These are the red Kate Spade plates that I used with my brownies.

Key to Success #3 – Frost Brownies as Soon as They Come Out of the Oven

During the last few minutes that your brownies are baking, make your chocolate frosting.

Use an electric mixer to whip up the softened butter, cocoa powder, and vanilla extract.

Then slowly add in the powdered sugar and milk.

When the brownies come out of the oven, stir the miniature marshmallows into the frosting then spread it onto the warm brownies.

The heat from the brownies will help the frosting seep into the brownies, making them extra moist and delicious.

Mississippi Mud Brownies

Spread the frosting over the warm brownies then let them cool completely before cutting them into squares.

They need time to really bring the flavors together. Don’t be tempted to dig into them before they’re cool.

They are worth the wait!

Save this Mississippi Mud Brownies recipe to your favorite Chocolate Dessert board or your Brownie board.

Mississippi Mud Brownies
Mississippi Mud Brownies

Mississippi Mud Brownies

Mississippi Mud Brownies are my dream come true – a thick and fudgy brownie covered with marshmallows and chocolate icing. No boxed brownie mix here. It's much better from scratch!
4.85 from 13 votes
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Course: Dessert
Cuisine: American
Prep Time: 15 minutes
Cook Time: 30 minutes
Total Time: 45 minutes
Servings: 24 servings
Author: Jennifer


For the chocolate frosting


  • Preheat oven to 350° degrees F.
  • Whisk together melted butter and cocoa powder. Stir in sugar. Add in beaten eggs and vanilla extract and mix well.
  • Stir in flour, salt and chopped pecans.
  • Spread batter into a greased 13X9-inch pan.
  • Bake at 350° for 30 to 35 minutes or until toothpick inserted in center comes out clean.
  • While brownies are baking, make the chocolate frosting: Using an electric mixer, beat together powdered sugar, cocoa powder, softened butter, vanilla extract and milk.
  • Remove brownies from oven. Stir marshmallows into chocolate frosting then immediately spread over hot brownies.
  • Let the brownies cool completely before cutting into squares.


Serving: 1grams
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