These Mississippi Mud Brownies are the definition of chocolate overload, in the best way possible. You’ve got a fudgey brownie base, gooey marshmallows melted right on top, and a rich chocolate frosting to seal the deal. They’re messy, indulgent, and impossible to resist…a little bit like Tim Riggins. Make sure to let them cool completely before cutting so you get those perfect, stacked layers in every bite. I firmly believe when coupled with a Diet Coke, they form the New Breakfast of Champions.
Ingredients & Equipment Needed
- Brownies:
- all-purpose flour
- sugar
- unsweetened cocoa powder
- baking powder
- salt
- butter
- eggs
- vanilla extract
- dark or semi-sweet chocolate chips or chunks
- mini marshmallows or flat marshmallows
- Frosting:
- butter
- unsweetened cocoa powder
- evaporated milk or whole milk
- powdered sugar
- vanilla
- 9×13 baking dish
How to Make Mississippi Mud Brownies
This is a simple overview of the recipe, you’ll find a full printable recipe below!
- Preheat oven to 350°F and prep a 9×13 pan.
- Mix dry ingredients, then add melted butter, eggs, and vanilla; beat until smooth. Stir in chocolate chips and spread batter in pan.
- Bake until set (time varies greatly, but definitely start checking early).
- Top with marshmallows, return briefly to oven until puffed, then cool completely.
- Whip frosting until fluffy, spread over cooled brownies, and slice into squares.
A Note About Baking Time & Other Tips
- Baking time: there is a bit of debate about how long these need to bake. Unfortunately, I don’t have a perfect answer, and there are a lot of variables. Here are the facts:
- These brownies should be moist and fudgy.
- The original recipe says to bake them for 30 minutes.
- I am essentially at sea-level and bake these in a glass Pyrex 9×13 pan.
- At 25 minutes (because I always recommend checking a few minutes before they’re supposed to be done), my brownies were just starting to firm up around the very, very edges of the pan and were completely liquid inside.
- I checked them every five minutes and they were done in the 45 – 50 minute range.
- Other people have had them come out dry at 30 – 35 minutes.
- If you’re baking them in a metal pan, they’ll take less time, especially if it’s a dark metal pan.
- Usually things at a low elevation bake faster, but apparently not in this case.
- Bottom line: start checking on them around 25 – 30 minutes and keep checking every 5 until the toothpick just barely comes out clean.
- Cutting: these can be kind of a pain to cut, especially getting the first few out, but just take your time and make firm, straight-down cuts (to make sure the marshmallows are getting cut), wiping the blade often. A plastic knife (just the disposable kind) actually works better than just about anything else.
Frequently Asked Questions
Watch for lightly set edges and a slightly soft center. A toothpick inserted in the middle should come out with a few moist crumbs.
Yes, letting them cool totally (including the marshmallow layer) helps the frosting set better and gives cleaner slices.
You can, just note that using a thinner or metal pan may change the bake time. Dark metal pans bake faster, and using a larger pan will thin out the layers.
I love the flat marshmallows for this recipe, but mini works great too. Just cover the surface well, so they distribute and melt evenly.
Totally! Just adjust the baking time as needed and ensure brownies are baked long enough to support the marshmallow and frosting layers without becoming soggy.
Mississippi Mud Brownies (Tim Riggins Brownies)
Ingredients
Brownies
- 1 ½ cups all-purpose flour lightly spooned into measuring cups and leveled with a knife
- 2 cups sugar
- ½ cup unsweetened cocoa powder
- 2 teaspoons baking powder
- ½ teaspoons table salt
- 1 cup butter, melted 2 sticks
- 3 eggs lightly beaten
- 1 tablespoon vanilla extract
- 1 cup dark or semi-sweet chocolate chips or chunks
- 3 cups mini marshmallows or enough flat marshmallows to cover a 9×13″ pan
Frosting
- ½ cup butter, melted
- ⅓ cup unsweetened cocoa powder
- ⅓ cup evaporated milk or whole milk
- 1 pound powdered sugar
- 1 teaspoon vanilla
Instructions
- Preheat oven to 350℉. Lightly grease (and flour, if desired) a 9×13" pan and set aside.
- Combine the flour, sugar, cocoa powder, baking powder, and salt in a large bowl or the bowl of your stand mixer. Add the melted butter, whisked eggs, and vanilla. Beat on medium speed for about 3 minutes, scraping the bowl occasionally.
- Add in the chocolate chips and spread the batter in the prepared pan. Bake for 25-40 minutes (or a little less if using a metal pan; please check out the notes on baking times in the post because they can vary a LOT) or until a pick inserted into the center of the brownies comes out clean.
- When the brownies are done, remove from the oven and spread the marshmallows on top. Return the pan to the oven for 2-3 minutes or until the marshmallows are puffed. Remove from oven and cool completely.
- While the brownies are cooling, beat together the frosting ingredients on high speed until light and fluffy. Spread over the cooled brownies and cut into squares. (Using a disposable knife works very well if you have one around.)
Questions & Reviews
I make a lot of buttercream frosting but this is the first time I’ve done it with melted butter. Then I had LOTS of lumps of powdered sugar/cocoa in my frosting. do you have any suggestions? Did this happen to you?
I would sift both before you add them–sometimes they get a little lumpy. Hope that helps!
Amen to Susanne’s comment! Your writing always makes me laugh! The new pictures are lovely as always but I did miss your comment on the original post about how you’d poked the brownies so many times they resembled a heroine addict! I read that to my hubby the last time I made these and we both got a kick out of that. I WAS glad to see the print recipe contained the note about the baking time varying as wildly as a drunken party at Tim Riggins 🙂 🙂 These brownies and this post are one our all time favorites!
Thank you!! <3
I love your blog and these brownies! What a great decadent recipe. You have such a fun personality too!
But i liked the old pictures…..
Is that vanilla a good one? Where do you buy it?
That’s just my homemade vanilla! 🙂
I clicked on this just because it said Tim Riggins 🙂
Hahaha!!
You forgot to put the part where to add in the chocolate chips. I baked mine not looking at the bottom since I thought the top had everything. They were still delicious but please add that for the sake of everyone else like me. Thank you!!
Made these last night! Very yummy. In case anyone is interested:
– I just halved the recipe because a) we didn’t have enough of all ingredients and b) husband and I didn’t really need a 13 x 9 of brownies to ourselves. 🙂 I put it in an 8 x 8 and it turned out well! I think it was probably about 30 minutes in the oven in a glass pan.
– I didn’t do the frosting layer because we didn’t have powdered sugar. Is that cheating? Just the brownies and marshmallows were delicious enough, though!
Thanks for a great (old) recipe!
You had me at Tim Riggins…..