Mississippi Mud Brownies

Last week, I was in the mood for brownies. I was in the mood for brownies with “stuff”. Not just any old plain brownie, but brownies filled, topped and layered with ingredients. It then dawned on me that even though I had made Mississippi Mud Cake a little over a year ago, I had never made the brownie version, which I’ve been meaning to do since I made the cake. I had everything I needed for the brownies, which was all the encouragement I needed. As we all know, there’s never a bad time for a brownie!
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Much like the cake version, these Mississippi Mud Brownies are rich, chewy brownies that are topped with marshmallows, covered in a fabulous chocolate fudge icing and sprinkled with chopped pecans. I took the blow torch to the marshmallows before covering them in the icing, which gives the brownies a faint toasted flavor. It’s perfect if you love s’mores! (If not, you can totally skip that step and it won’t negatively affect the brownies.) I can’t resist chocolate and marshmallows together, so these brownies are right up my alley.
What’s your favorite way to jazz up plain brownies?
Two years ago: Chocolate Chip Cookie Dough Brownies and Everything Bagels
Three years ago: Homemade Pop-Tarts
Four years ago: Anise-Almond Biscotti and Better-than-Brownies Chocolate Cookies

Mississippi Mud Brownies
Ingredients
For the Brownies:
- ½ cup (62.5 g) all-purpose flour
- ½ cup (43 g) unsweetened cocoa powder
- ¾ cup (150 g) granulated sugar
- ⅓ cup (66.67 g) packed light-brown sugar
- ¼ teaspoon (0.25 teaspoon) salt
- ½ cup (113.5 g) unsalted butter, melted and cooled slightly
- 2 eggs
- 1 teaspoon vanilla extract
- ¾ cup (74.25 g) chopped pecans, divided
- 2½ cups (187.5 g) miniature marshmallows
For the Fudge Icing:
- ¼ cup (56.75 g) unsalted butter
- ¼ cup (61 ml) whole milk
- ¼ cup (21.5 g) unsweetened cocoa powder
- ½ teaspoon (0.5 teaspoon) vanilla extract
- 2 cups (240 g) powdered sugar
- Pinch of salt
Instructions
- Make the Brownies: Preheat oven to 325 degrees F. Line an 8x8-inch square baking dish with aluminum foil and coat lightly with non-stick cooking spray.
- In a large bowl, whisk together the flour, cocoa powder, granulated sugar, brown sugar and salt until blended. Using a wooden spoon, stir in the melted butter and mix until combined. (The batter may get hard like fudge at this point.) Add the eggs and vanilla extract and stir until blended and no clumps remain. Fold in ½ cup of the chopped pecans. Pour the batter into the prepared baking dish and bake for 35 - 37 minutes, or until a thin knife or skewer inserted into the center comes out with very moist crumbs attached.
- Remove from the oven and sprinkle the marshmallows evenly over the top. Return the pan to the oven and bake until the marshmallows are slightly puffy, about 4 minutes. Remove from oven and place on a wire cooling rack. Allow the brownies to rest for 5 minutes, then toast the tops of marshmallows with a kitchen torch (this is optional).
- Make the Chocolate Fudge Icing: In a small saucepan, melt the butter over medium-high heat, stirring frequently. Add the milk and cocoa powder and cook, whisking constantly, until the mixture has thickened, 1 to 2 minutes. Remove from the heat and add the powdered sugar, vanilla and salt, and beat with an electric mixer on medium speed until the frosting is smooth.
- Immediately pour and spread the chocolate icing evenly over top (work quickly as the icing begins to harden as soon as it's made). Sprinkle the top with the remaining chopped pecans. Allow to cool completely and cut into squares. The brownies can be stored in an airtight container at room temperature for up to 5 days.
Notes
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Delicious! My family scarfs up these brownies every time I make them.
I just wanted you to know that this is my go-to site for recipes – if I can’t find it here, THEN I go to Google. ;) And I tried this recipe & it was so fabulous! Except for the store for 5 days part – they barely made it 24 hours in my house!
Will definitely try this one. Thanks for sharing all of your favorite recipes. I already tried the Chewy Brownies and it is a No-Fail, although I substituted the bittersweet by unsweetened and unsweetened by semi-sweet, still it’s the best brownies I ever tried. THANKS :)
I just have to let you know this is now my go to brownie base. It is perfect!!!
Hi Mihelle,
Thanks a lot for this wonderful recipe, I just made these :) I just have one question, aren’t the marshmellows supposed to melt? Mine didn’t melt at all… they were puffy though when i took them out of the oven…I did put the icing and everything as you wrote in the recipe, but in your pictures, the marshmellows look melted and soooo yummy…
Thanks again for the very very beautiful blog <3 I can't stop baking :)
They should be puffy out of the oven, but then once you put the icing on, it kind of smooshes them down to a full melt. Maybe they just needed a little extra time in the oven?
These look great! Could I possibly substitute butter milk for the regular milk in the icing?
Hi Katie, I would not recommend using buttermilk in the icing; I would stick to regular milk.
We always used marshmallow crème instead of actual marshmallows. Put it on top of the hot brownies and it begins to melt. Then we poured on the fudge and spread it. It was so rich we could only eat a small piece at a time. I like the idea of putting some nuts on top.
These were very delicious recipes and i have enjoyed alot…..
I just made them, they are delish. I have to say though, they are bit on the sweet side, maybe a little less sugar in the Icing?