Mississippi Mud Bars
The brownie + marshmallows + toasted pecans + fudge sauce combo has never been tastier (or easier!). These Mississippi Mud Bars are insanely delicious and so simple to make!
These bars! Seriously, amazing. Prepare to wow your friends and family with this tasty little Mississippi Mud concoction.
I made them recently for a church event and was kind of surprised at how many people were excited about them.
Maybe the fact that the event was a Cub Scout Pinewood Derby should be honestly disclosed. A group of energetic, mildly stinky boys (I can say this as two of them are mine) who would willingly eat crumbled off-brand Oreo crumbs off a gym floor may not be the most objective of dessert judges, I know.
But I still validate their honest feedback (even if I did have to hold the pan over my head and threaten to take the wheels off their Pinewood Derby cars if they came back for a 5th bar without washing their hands – or asking their mom first).
AND judging by the fact that many of the parents asked for the recipe, I can safely and comfortably recommend these bars for all of your future event/potluck/late night binging needs.
I was initially skeptical that these bars could fulfill my chocolate-loving dreams because the brownie/cakey base is so…well…thin.
And I don’t know about you, but “thin” as a descriptor doesn’t belong anywhere near a pan of decadent, chocolatey brownies, in my opinion.
However, the ultimate result of topping soft and rich brownies with marshmallows and then pecans and then a chocolate drizzle far, far exceeded my expectations.
The equal parts brownie to marshmallow ratio is what makes these Mississippi Mud bars so divine. Basically, thin brownies are welcome here.
The brownie cake layer (it really is a cross between a brownie and a cake in terms of texture and flavor) mixes up all in one bowl, which makes the assembly of these bars ultra-easy.
Then, once they are baked, marshmallows are dumped on top and softened for just a few additional minutes in the oven before getting a dose of toasted pecans.
And speaking of pecans, I know there are organizations dedicated to the hatred of nuts in desserts…and an equal number of people who fight the opposite side.
I’m somewhere in the middle. 99% of the time, I opt OUT of nuts in any of my brownies or cakes (total exception for these white chocolate pecan brownies and a few other divine special cases).
But without the pecans, these Mississippi Mud bars just aren’t complete, and I, personally, loved the toasty crunch. Coming from a semi-nut hater, that should give you a small push to add them if you are on the fence.
Toasting the pecans is optional, but the level of flavor boost is pretty significant, so I definitely recommend doing it (or buying toasted pecans…I know Trader Joe’s carries them?).
Also, please make sure when you get to the step of The Chocolate Drizzle that you take great care to apply the chocolate sauce to the top of the bars in a very defined, precise, geometric pattern.
You might consider sketching the drizzling action on a sheet of graph paper first, as perfection is the only acceptable method here.
Haha.
Just kidding.
Go crazy and drizzle your heart out until it looks messy and absolutely delicious.
As you can see from the pictures, these Mississippi Mud bars are sheet pan style.
So great and practical for potlucks or events where you are serving a lot of people.
I know a good food blogger worth her salt would have experimented to cut the recipe down and make it in a 9X13-inch or smaller pan.
But that food blogger is not me today.
I love sheet pan recipes like this because I so often need a large and in charge dessert to take to church events or family get togethers or whatever else comes on the horizon (yes, even a night in with the family will sometimes justify an enormous sheet pan splurge).
However, as noted in the recipe, I think there’s a good chance the recipe could be halved and baked in a 9X13-inch pan. Someone report back if they try it? Thanks. 🙂
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Mississippi Mud Bars
Ingredients
Bars:
- 1 ⅓ cups (189 g) all-purpose flour
- 1 cup (212 g) granulated sugar
- 1 cup (212 g) brown sugar
- ½ cup (43 g) unsweetened cocoa powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- 1 cup (227 g) salted butter, melted
- 4 large eggs
- 1 teaspoon vanilla extract
- 10-ounce package (283 g) mini marshmallows
- 1 cup (120 g) chopped pecans, toasted (optional but delicious)
Chocolate Topping:
- ⅓ cup (28 g) unsweetened cocoa powder
- ¼ cup milk
- ¼ cup (57 g) salted butter
- Pinch of salt
- 2 cups (228 g) powdered sugar
- 1 teaspoon vanilla extract
Instructions
- Preheat the oven to 350 degrees F. Line a large, rimmed baking sheet (half sheet pan, about 12X18 inches) with parchment and lightly grease with cooking spray. Alternately, you can line with foil and grease the foil or leave the pan unlined and grease the pan.
- For the bars, in a large bowl, whisk together the flour, sugar, brown sugar, cocoa (sift the cocoa into the bowl using a fine mesh strainer if it is overly clumpy), baking soda and salt. Add the melted butter, eggs, and vanilla. Mix together until combined (don’t overmix; just whisk/stir until no dry streaks remain and ingredients are evenly combined).
- Spread the batter evenly in a thin layer in the prepared pan. Bake for 15-20 minutes until the top is springy to the touch and a toothpick inserted in the center comes out clean. Watch closely so the thin bars don’t overbake!
- Remove from the oven, sprinkle the top evenly with marshmallows, and bake for 3-5 minutes more until the marshmallows are softened.
- Sprinkle with pecans and let cool to room temperature before glazing.
- For the chocolate topping, in a medium saucepan, whisk together the cocoa powder (I sift it in to avoid clumps), milk, butter, and salt. Bring the mixture to a gentle boil over medium heat, stirring or whisking constantly.
- Remove from the heat and whisk in the powdered sugar and vanilla. Thin with additional milk, if needed, until the mixture is thick but pourable and can easily be drizzled across the bars.
- Drizzle the glaze in a crisscross pattern across the bars. Serve the bars warm or at room temperature. They are easier to cut if they’ve been cooled completely.
Notes
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Recipe Source: adapted from a recipe *I think* I tore out from the Bake From Scratch magazine
I doubled the recipe and baked in a 18×24, upped the bake time to 25 minutes before adding te marshmallows, worked great! It’s one of our faves:)
Also no need to double the chocolate topping, as the recipe is still make plenty!
Hi, we’re going to be going camping in a few days and I’m curious as to how far in advance I could make these. Do you think they would last if I made them Saturday morning and we had them Sunday night? Thanks so much for the recipe, I’m excited to try it!
I think that would be ok! The marshmallows might get a bit softer and slightly sticker if made ahead of time, but they should still be pretty good. Do you have a way to refrigerate them?
I made this for a church luncheon. They were so delicious I can’t wait to have more!
I made these for 40 teenage boys along with Mel’s chocolate chip cookie bars and some other caramel Rice Krispie treats. These disappeared the fastest with the boys begging for more! Next time I’d do double of these! They were so good. I did them without the pecans to a solid any allergy issues and they were still amazing.
These were really easy and delicious!
So if I double it a regular sheet pan should work right? I am thinking of making them for a large family reunion. Two sheet pans, one with nuts and one without.
I haven’t tried a double batch in a full sheet pan, but you could definitely experiment!
We loved these! My husband used a buttered pizza cutter to cut them and he said it worked like a charm.
Can these be made the night before?
Yes!
These were amazing! I loved them so much. I was going to give them to some neighbors and friends but they were gone before I could. Thanks for sharing this recipe. It is definitely a favorite! 🙂
I came across this recipe recently while I was looking for something new to bake for my four children (ages 9 – 20). I bake something every couple of days so I always have something homemade in the house. I made the recipe as written but baked it in a 9×13 pan (foiled & greased). I baked the brownie base for 19 minutes, then covered with marshmallows (a lot – easily 3/4 of a bag) and baked 4 more minutes. My children all loved it, and have requested (insisted, demanded…) that this be added to the list of regulars. You have yet to let us down, Mel. My family knows when I say “This is one of Mel’s recipes” that they are in for a treat! Thanks for another winner!!
Thanks, Edie – your kids sure are lucky!
Mel, if you use a plastic knife, you won’t have trouble cutting your brownie or bars-baked-in-a-sheet-pan.
Hi ! Could you put the amount of Calories, Fat, etc for your recipes? I’m trying to lose weight but your cakes look so good
Thanks! Dottie
Making these for Labor Day, actually had to through a (small) party just for the excuse! Do you think I could make these in a 9×13 pan even if I didn’t half the recipe, for a thicker brownie? Thanks for keeping us well fed!!
Yes! You may not need as many marshmallows for the topping though.
Rogue marshmallows. Sounds like a band name!
Mel, These were a hit at church. Thanks for a great easy dessert!
Boom baby! So good. Make them!
Thinking about taking these to a church BBQ. Would you suggest leaving them in the sheet pan or serving from a platter?
Honestly, I think either could work just fine! After cutting, if they are left on the sheet pan, the marshmallow tends to kind of stick back together, so it might be easier serving them from a platter so they can pick them up and go, but if there is a spatula on the sheet pan, they can still gently pry the bars apart.
These are super yummy!
I didn’t have pecans on hand, so I chopped up 4 sheets of graham crackers and used those instead! Then, I broiled the marshmallows at the end to make them smores-y!
I love bars in a sheet pan…I feel like I get a lot of bang for my baking buck!
Also, I meant to do 5 stars!…
Love the variations, Becky!
Wow, these are amazing. I’ve made them twice now, one for church choir and the second for a piano recital. They were a big hit! They are very easy to make and not too rich. They also look amazing!! Thank you for this recipe!
Thanks, Sharese!
These were not a favorite, but we are not cake people. I’d prefer just a plain brownie recipe. I have toasted marshmallows on brownies before, but I wouldn’t recommend starting them on fire like I did! However, they did taste a lot like s’mores!
These were delicious and so easy to make! YUM.
Thanks, Christina!
I made them ahead of time! Should I refrigerate until my party tomorrow afternoon once they have cooled completely?
So excited for them!
The marshmallows might soften a bit after refrigerating, but yes, I would refrigerate.
Always looking for something new to serve my lunchtime catering clients. These were well received. The brownie on the bottom is thinner than I had wanted, but there were still able to be stacked and picked up with ease. Used walnuts as a cost-saving decision. Anything on a sheet pan is right up my alley.
Father, forgive Mel for she knows not what these do to my hips. Amen.
🙂
Made these last night for my daughter’s birthday cake. Wow! They were delicious. She loved them.
Yay!
I’m a huge fan of your site! I made this tonight and the bars were easy to make, but I’m not sure what I’m doing wrong on the chocolate glaze. I’ve made it twice and had to throw it out twice. I followed the directions, but instead of boiling, it separates and it gets really thick and unappetizing looking. Any ideas what I’m doing wrong? Trying again with adding a lot more milk…
Darn, Jenna! Try increasing the milk to 1/3 cup and whisk the whole time it comes to a boil to see if that helps?
Hi, Mel! I could not resist halving this recipe & making these gooey beauties! My 9×13 pan worked well, tho the thick batter did not reach all the way to the corners, & I actually could have baked them even longer than the 25 mins they were in the oven. Seeing the marshmallows puff up during the 2nd bake was a thing of beauty, & the toasted nuts added an extra fab dimension. I think I must have been heavy handed with the milk in the choc sauce, so my choc splatters looked less exciting than yours tho. Keeping in mind your advice of short movements while cutting these bars was very helpful to me. Halving the recipe for a 9×13 works for these yummy brownie bars!
Thanks so much for the report back, Lauren! Glad these worked out for you as well in a 9X13-inch pan!
Mississippi Mud Bars! My favorite dessert for many years!
Try them with cherries too- delicious!
A new favorite! My 11yo son needed only minimal help with this and boy, it delivered! I was reading off the directions to him throughout, and when I got to the part about the glaze, I read what you said about perfect geometric shapes and sketching it out first. He was pretty concerned! Ha ha! When he realized it was a joke, he made sure to drop a giant blob in one place and declare that piece his. 😉 This recipe is a keeper! Easy, delicious, feeds a crowd, and looks fantastic.
Hahaha! This made me laugh out loud! I’m sure your son was like “um, Mel is crazy!” – glad he figured out it was a joke! So glad you loved it…and tell your son, I think he’s awesome for making them by himself!
I completely forgot about Teacher Appreciation today and was SO glad we had plenty of these left to share (made the full batch). I ran some over at pick-up time. One teacher (the 11yo’s) came back out teary about them and was so touched my son made them! Ha ha! Everyone wins!
Because I love you Mel and I’m completely selfless (ha!), I halved the recipe & made these in a 9×13 tonight for FHE and it was gooey chocolatey perfection.
It did take 25 minutes for the brownies to cook so a toothpick came out clean (glass pan lined with greased foil). I highly recommend lining the pan if using a 9×13 to make cutting easier– just make sure there’s some extra foil or parchment paper on the sides then lift it out after a bit of cooling to cool the rest of the way.
Pecans are expensive where I live so I candied some chopped walnuts– we loved the crunch & varying texture they brought!
Fellow readers: these are rich so you’ll probably want to cut them on the small side for serving 🙂
Way to take one for the team and try it out in a 9X13, Chelsea! I love you for that. 🙂 Thanks for all your insight! It is invaluable when you awesome readers leave comments like this.
My Follow Up! I’m so glad I didn’t try any of the other recipes that I somehow knew would be a disappointment… These were so worth my 2 weeks of unsatisfied craving. These brownies are everything I wanted them to be and more!!! Thanks for knowing exactly what I needed today!! We have already eaten 1/4 of the Pan… Yummy !!
Yay, yay! I’m so happy these delivered, Helen!
Oh Man!!! You read my mind! I have been searching for 2 weeks for a yummy marshmallow topped brownie and nothing has jumped out at me, so I have just continued with the craving… I was at the grocery store today and bought marshmallows with the plan that I would make your most recent brownie recipe post and then melt marshmallows on them after they were done. NOW I come to your website to get the brownie recipe and this is the first thing I see!! I am going to make these in the next couple of hours…. I will come back and report, The Universe is smiling on me today 🙂 Thanks Mel!!!
The pop ups and ads on this site are really disruptive and annoying. they ruin the flow of an article your trying to read. as soon as you click one off, here comes another.
Sorry to hear you are having a less than great experience. What device are you using? Are you on a desktop computer or a mobile device or tablet? I’ll definitely look into it; there definitely should not be any pop up ads ever.
I’m guessing this person is referring to the picture ads that are embedded in the article. I’m on my Android phone and there is an ad above or below every single picture in your posts. So this post has 9 picture ads by the time you get to the recipe. I agree they are annoying, but they are pretty normal these days and I completely support you getting money for your efforts by putting ads in the posts, so I just keep scrolling. Thanks for another yummy recipe.
Thanks for the feedback, Jennifer. I agree that ads can be super annoying – I’ll change some settings to see if I can lower the amount of ads per post a bit. Thanks for the comment (and the support). 🙂
YUM!!! I would love these cooked in a 9×13 pan just as they are. Not half the recipe. HA!! Just would have to cook longer.
Could these be made ahead and frozen? I’m asking because I’m not sure about what happens to marshmallows if they’re frozen.
Hi Laurie – I haven’t tried freezing them, mostly because I haven’t had great luck freezing marshmallow desserts like this (where the marshmallows are baked on top) in the past. They get super sticky and mushy once they are defrosted.
I took one for the team and tried freezing half of the batch and I thought they were delicious. In full disclosure, I did eat several off them straight from the freezer. But, my kiddos took them to school in their lunches and they said the thawed brownies awesome.
You deserve an award for this, Holly. Thanks for being the guinea pig, And I, too, would have dug straight into the freezer to try one – I mean, you know, research purposes and all that. 🙂
More dessert recipes in sheet pans please – love them for sharing and potlucks!!