Marshmallow Boxed Brownies Recipe
You’re all probably going to think I’m crazy, but I don’t care. I stumbled across something amazing, and I just can’t keep it to myself. I feel I must spread this news to anyone who will listen. If there was ever a brownie recipe that was going to change your life, it’s this Crazy Good Marshmallow Boxed Brownies recipe. Coming in at a close second are these German Chocolate Brownies…which are from so long ago, no one ever sees them. So click on it now, and bookmark it to make after you try this insanely delicious and simple boxed brownie recipe.
A few months ago, I saw an Instagram post from Cooks Illustrated ranking different boxed brownie brands. They asked everyone to comment with their favorite brand. Somehow I got sucked into reading hundreds of responses, you know, for research’s sake. There were a few things that I saw over and over in the comment section that made me think, “Hmm, maybe I need to be doing that with my boxed brownies.”
One of the things recommended over and over that people swore made them more delicious was subbing coffee for the water. I know coffee can really enhance the cocoa flavor and makes chocolate cakes extra delicious, so this was not hard to believe. Then there was a second interesting recommendation, but this one only came up twice. The conviction, however, of the two commenters that it was the ONLY way to make boxed brownies really piqued my interest. They are saying to stir an entire bag of mini marshmallows into your brownie batter.
What now? You, people, are crazy!
I lasted about a day before I decided I absolutely had to try it. Verdict: It’s freaking delicious!!! Granted, I was scared to put the entire bag in, so I went with about 2/3-3/4. (You can measure with your heart how much you’re going to add.) But wow! It’s such a surprise. I didn’t know what to expect, but the marshmallows kind of melted into the batter, making it out-of-this-world chewy. The marshmallows close to the top and edges got just a little crispy, which–WOW! What a combination. I’m usually not an edge or corner brownie person, but I am with these. I literally can’t wait for you to try this and to hear how you feel about it. I’m hooked!
You will see in the recipe card that I did substitute the water for coffee and also added about a half cup of chocolate chips. I used instant coffee and just added some hot water to a tsp of it and let it sit for a few minutes before adding. It really kicks up the chocolate flavor. If you don’t have coffee, don’t worry. Your brownies will still turn out fabulously chewy and irresistible!
More Awesome Brownie and Bar Recipes
- Best Homemade Brownies Recipe
- Perfect Mint Brownies
- Swig Sugar Cookie Bars Recipe
- Hello Dolly Bars
- Chocolate Caramel Slice
- Rolo Carmelita Bars
step-by-step photos for how to make Crazy Good Marshmallow Boxed Brownies
Frequently Asked Questions for how to make Crazy Good Marshmallow Boxed Brownies
Why do the brownies need to cook longer than stated on the box?
Once you add the marshmallows, the brownie batter fills the baking dish to a higher level and makes it take longer to cook because it is denser.
Will this overflow if I bake it in a 9×9 instead of a 9×13?
I haven’t tried to bake it in anything other than a 9×13. It would definitely take much longer to bake, and if it didn’t overflow, it would come very close.
Do semi-sweet or milk chocolate chips work better in this recipe?
This is a personal preference. I prefer semi-sweet in this recipe
Can I use regular-sized marshmallows in this recipe?
I haven’t tried to make this with regular-sized marshmallows. I think it might not work very well. If you only have regular-sized, I would suggest at least cutting them in half or fourths, if you can.
Can these brownies be made ahead and frozen?
Yes. These brownies freeze really well. Just make sure you have them in an airtight container. I have made them, cut them into squares, and frozen them in individual ziplock bags to put in my kids’ lunch boxes.
BAKER’S TOOLS for Marshmallow Brownies:
If you love Marshmallow Boxed Brownies, you'll love these...
- 1 (18.3 oz) boxed brownie mix (I prefer Duncan Hines.)
- 3 tbsp prepared instant coffee or water
- ⅔ cup canola oil
- 2 eggs
- 1 (10 ounce) package mini marshmallows
- ½ cup chocolate chips
- Preheat your oven to 350 degrees Fahrenheit.
- Spray a glass 9x13 baking dish with cooking spray and set aside.
- In a 2-quart mixing bowl combine the dry brownie mix, the prepared instant coffee (or water), canola oil, and 2 eggs.
- Mix with a fork for about 50 strokes or until completely mixed but not overmixed.
- Next, add marshmallows and chocolate chips. Mix until all marshmallows are covered with batter.
- Spread batter evenly in the prepared 9x13 baking dish.
- Bake at 350 degrees for 26-32 minutes or until edges are darkening and brownies seem nice and set. Putting a toothpick in is not as helpful with this because you may hit a marshmallow area, which can still appear like wet batter.
- Let brownies cool completely before cutting.
- Enjoy!
I’m diabetic and would like to see nutritional information.
Hi Betty, I’m so sorry but I don’t calculate nutritional info on my site. I’ve heard there are websites that you can type the ingredients and amounts into to find out that info.
Ready to make these but hesitate because you mention using a glass 13×9 pan. Is this necessary to the recipe or can I use my metal pan of same size? And, like you, I am intrigued by this recipe and can’t wait to bake these.
Hi Barbara, You can definitely use a metal pan. I am so excited you are making them. They are sooo yummy!
Absolutely the best brownies I have ever tasted. I made these for my husband’s birthday, he loved them. You were right the marshmallows melted into the batter and made them oh so rich. Thanks for sharing such wonderful recipes!
Right! Aren’t that just crazy good! I love them so much, I can’t stop making them for any excuse that comes up.
Have you tried doubling this recipe?
Outcome or suggestions if you have experimented ~
Thank you!
Hi Jackie, I haven’y tried doubling it, but as long as you put it in a big enough pan it should be fine. Just watch it and see if you need to adjust cooking time.
Not sure what I did wrong. These were the worst brownies I ever made. Maybe it was the quality of the brownie mix? Maybe I should have used the amount of oil recommend on the box? Too many marshmallows? They were super thin, and way too gooey. More like candy than a brownie.
I am sorry to hear that. Could it be that they needed to cook longer. Depending on the oven the cooking time may need to be increased or it can be very batter like. Or was it a smaller than normal brownie mix?
Boxed mixes contain less now. Sadly, this will affect some old recipes. https://shorturl.at/Xi4qs
Just wanted to let you know I tried to sign up to receive other recipes from you, but the sign up is not working. Just thought I would let you know.
Thank you
Thanks, Rhonda. I have passed that information on, and hopefully it will be fixed soon.
Getting ready to try these. Why did you use 2/3 c. oil rather than 1/2 c. called for on the box?
Hi Karen, I just fixed it. I think different brands call for different amounts. The one I was using called for used 2/3. I added to use whatever amount the brownie mix calls for. Thanks for bringing that to my attention.
I made this recipe today, and it was absolutely delicious. I used three tablespoons of water and 1/4 tsp of espresso powder because I didn’t have coffee.
Awesome! I am so glad you liked them. They are one of my favorites!
Do I have to use the chips?
No, they will be great with or without.
I’ve made brownies for years adding chocolate chips and marshmallows but never this many. Our family and church friends loved them and want the recipe lol. Thank you!
The chewy factor is just to die for with this many marshmallows. So glad your family and church friends loved them!
I assume you mean instant coffee that has already been made – not just the coffee granules, since the alternative is water? What if I use regular coffee – not instant? I mainly need to know whether I’m adding liquid or powdered coffee/granules?
Yes, and regular coffee would totally work!
Well since I put in granular instant coffee (no water since you said annuals and I figured maybe it dissolves in the oil) and then the oil being 2/3 cup it’s doubtful that this will come out correctly. Perhaps before you publish a recipe that’s to die for, you make sure that it’s correct. Disappointing.
I apologize that that wasn’t clear, I thought that by saying instant coffee or water it would be implied that it was prepared instant coffee. There is also a picture in the step by step pictures of it. I apologize I can only imagine how gross yours turned out with three tablespoons of coffee granules. I am really sorry.
Maria, your reply was the most gracious reply to something that was not your mistake that I could imagine. Kelly said, “I assume you mean instant coffee that has already been made.” You said, “Yes.” Why she would go ahead and use granules is beyond me, but certainly not your fault. Although the brownies sound great, I’m going with a sugar free marshmallow substitute to ease my conscience
Thank you, yes, they are full of sugar, let me know how they turn out with the sugar free marshmallow substitute.
Goodness. Are you sure you didn’t put a lot of SALT in your brownies? Disappointing.
These are in the oven as we speak! 😁