Mom’s Famous Chocolate Marshmallow Brownies

Mom's Famous Chocolate Marshmallow Brownies are gooey goodness. The melted marshmallows on a chocolate base, topped with creamy homemade frosting, is probably the world's best combo.

I wish these pictures were scented because they smell almost as good as they taste. The chocolatey goodness with a layer of melted marshmallows will bring your tastebuds to life.

These brownies are so easy to make, and you are going to love them.

These soft chewy brownies are topped with a decadent chocolate frosting. Below we take you step by step, how to make the best chocolate frosting. It’s easy, delicious and is made within a matter of minutes.

I know that we have already shared this recipe on our blog, but they are so good, they deserve a second post.

Besides, I think that when we first posted them, our blog was just starting out and probably our only reader was our mom.


The story behind mom’s Famous Marshmallow Brownies

I had to put “Famous” in the title because our mom is seriously famous for these amazing brownies.

When we were growing up, our mom would make these brownies all the time, but it was usually for someone’s birthday,  for a sick friend, or a neighbor that just had a new baby.

When mom did make a pan just for our family, it was always a special treat. And we could eat the whole pan in a matter of hours.

I now make these brownies quite a bit because they are easy and it makes a TON so they are perfect to share with neighbors, or take to a potluck party.

Or eat the whole pan if you feel like it. I won’t judge you.

Related recipe:
If you love marshmallows and brownies, be sure to check out our Homemade S’mores Brownies!


Watch how to make these brownies here:

Did you know we have a Youtube Channel? Watch how to make Mom’s Famous Marshmallow Brownies!

How to make Marshmallow Brownies

Step 1: In a medium size bowl, soften margarine and blend in the sugar and cocoa until well combined.

Step 2: Add the eggs to the mixture one at a time, and blend until smooth.

Step 3: Add flour, salt and vanilla and continue to combine until everything is fully mixed.

Step 4: Grease a cookie sheet (half sheet size) with non stick cooking spray. Pour the brownie batter into the pan and spread out with a greased spoon or knife.

Step 5: Bake for 22-25 minutes at 350 degrees.

Step 6: Remove from oven and spread an entire bag of mini marshmallows over the hot brownies. Be sure to cover up as much brownies as you can. Place the brownies back in the oven for 3 minutes.

Tip: Do not cook for longer than 3 minutes or your marshmallows will burn and be crunchy. You want your marshmallows to be soft and not chewy.

Step 7:
Let brownies cool completely before frosting.

Step 8: Cover the brownies with chocolate frosting. For a homemade chocolate frosting recipe, read below. We have just the right amount of all the ingredients to make your frosting perfect.

How to make Fail-Proof Chocolate Frosting

Homemade frosting can be a little tricky. I could never get it right at first, then I came across this recipe, and ever since then, I haven’t had a problem with my frosting. It comes out perfect every time! Here is how you make it.

The key is to follow the ingredients measurements perfectly and in the right order. It’s also important your butter is at the right consistency.

Step 1: Soften your butter. This does not mean melt. This means room temperature. If you are in a hurry, and just got the butter out of the fridge, cut it into centimeter width slices and microwave for 15 seconds.

It’s okay if there is a little bit of melted butter at the bottom of the bowl, but you do not want to melt all of the butter or your frosting will be thin and end up looking like more of a glaze than frosting.

Step 2: Add the milk, vanilla, cocoa and powdered sugar to the bowl. Add them one at a time and continue to mix with a hand mixer.

We find that the powdered sugar and cocoa combines best without lumps when you use a hand mixer. You could also use a whisk, but to save yourself some time and an arm workout, we definitely recommend a hand mixer.

If the frosting isn’t to your desired thickness, you can also add a little more powdered sugar. Remember that you can always add more, but you can’t always take it back. You will want to start small with the powdered sugar and add a little at a time.

Step 3: Mix until the frosting is smooth.

Step 4: Spread over the cooled marshmallow brownies. It’s important to let the brownies cool before adding the frosting or else the frosting will melt and become more of a glaze.



Serves: 30-35

Mom's Famous Chocolate Marshmallow Brownies

40 minPrep Time

22 minCook Time

1 hr, 2 Total Time

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  • For the brownie:
  • 1 cup butter, softened to room temp (can use half butter half margarine)
  • 2 cups sugar
  • 1/3 cup cocoa
  • 4 eggs
  • 1 1/2 cup flour
  • 1 tsp salt
  • 2 tsp vanilla
  • 1 (10 oz) package of miniature marshmallows
  • For the frosting:
  • 1 stick margarine or butter (1/2 cup), softened
  • 2 tablespoons milk
  • 1 teaspoon vanilla
  • 3-4 Tablespoons of cocoa
  • 3 cups of powdered sugar


  1. For the brownies:
  2. Soften margarine and blend in sugar and cocoa.
  3. Beat together and add 4 eggs, one at a time, mixing after each one.
  4. Add flour, salt and vanilla and mix well.
  5. Spread on large half sheet baking pan that has been lightly greased. They are about 18 x 13 x 1 inch.
  6. Bake 22-25 minutes at 350.
  7. Remove from oven and cover entire top with 1 package of miniature marshmallows.
  8. Return to oven for 3 minutes, until marshmallows are soft and puffy.
  9. Cool and frost with chocolate frosting.
  10. For the frosting:
  11. Mix all ingredients with a hand mixer until smooth.
  12. Add more powdered sugar or milk until you reach desired consistency and spread on top of bars.



884 cal


6 g


161 g


42 g
Click Here For Full Nutrition, Exchanges, and My Plate Info


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66 Responses to “Mom’s Famous Chocolate Marshmallow Brownies”

      • Jane Waller
        I made these wonderful brownies. I do have questions. I used the 18x13x1 inch pan. The brownies were so thin but still fabulous. I noticed in one place you say use half sheet. Is that something I could buy? In another place you say 15 inch . I am confused as to what size sheet to use. Also, you say buttermilk to use for the icing and in the ingredient list, you say milk. Which should be used? I will be making these for the rest of my life so I need to have everything just right.
        • Hi Jane. I am mom and I can help you. A half sheet is basically our cookie sheet size. It measures 18 x 13 along the top edge. In the bottom of the pan it's closer to 17 x 12. So you are using the right size pan. I'm not sure why the girls said buttermilk in the frosting. I don't use buttermilk in our chocolate buttercream frosting. Just regular milk. I like to mix the brownies with a hand mixer. I have also found the Kraft mini marshmallows work the best. I've tried store brand and sometimes they flatten really weird. When buying the Kraft mini mallows, try to find a package that has air in it so the marshmallows wiggle around a little. You want them to puff up nicely. I usually stick the brownies back in the oven with the marshmallows for 3 minutes. I hope all of these tips help you. These marshmallow brownies aren't really thick in the cake part. But after you have the cake layer, marshmallow layer, and then the frosting layer - they are a nice thickness. If I want a thicker brownie, I make our Fudgy Brownies and then add marshmallow layer (for 3 minutes back in the oven) and frost when cooled. They are very thick and chewy but are made in a 9 x 13 inch pan. So you wont' get as many, but they are a thicker brownie. Let me know if you have more questions.
          • Jane Waller
            Thank you! These are the best brownies I have ever had. I make them a lot now. Thanks for clearing up a few things. I love Six Sisters recipes.
  1. Mary Jane
    Just made these on our second crazy snow day, your mother should have a star on the Hollywood Walk of Fame for this recipe! THE Y ARE AMAZING! I didn't have any mini marshmallows in the pantry so I cut the legones Iin half with kitchen shears that were greased with shortening. Extra work but they were so worth it. Need to take half the pan to my neighbour to remove temptation (under the guise of sharing) lol
  2. Richelle
    I have made these brownies multiple times for parties and there are never any left. They are amazing. I use the colored mini marshmallows and drizzle the chocolate frosting (made a little thinner) just to give it a more colorful/fun look for the kids. Absolutely the best brownie ever! Thank you!
    • When I want to make brownies in a 9 x 13 inch pan, we ususally opt for our Fudgy Brownie recipe. Then we still follow the steps with the marshmallows. After the brownies are done cooking, cover the top with mini marshmallows and stick back in the oven for about 3 more minutes. Let cool and frost. They are amazing and super fudgy and a little thicker.
    • This is basically the recipe for the frosting - 1 stick margarine or butter (1/2 cup), softened to room temp 2 tablespoons milk 1 teaspoon vanilla 3 tablespoons of cocoa 3 cups of powdered sugar Beat above ingredients all together with a hand mixer. If the frosting is too runny add more powdered sugar. If it's too thick add a little more milk. If you want it to be a darker chocolate taste and color, then add in another 1/2 tablespoon of cocoa. Hope this helps. Let me know if you have any other questions.
    • Mom's famous Chocolate Marshmallow Brownies are for a pan the size of a cookie sheet. If you want a good brownie for a 9 x 13 inch pan, I would recommend making the Fudgy Brownies. After cookinf them, you can add a 10 ounce bag of mini marshmallows and cook for about 3 minutes. Remove from oven and let cool. Then frost as directed in the recipe. They are thick and fudgy! (In fact, I made them yesterday with marshmallows!)
  3. My brownies came out very dry and crumbly. Marshmallows do help hold them together but they're somewhat hard to serve. Not sure what I did wrong. (I think my cookie sheet may have been bigger than what was listed but didn't measure, its just what I had).
    • Hi Kat. We are sorry that they didn't turn out. We have never had a problem with them. The bottom is very moist and far from dry and crumbly. We used a half sheet jelly roll pan that is approximately 16 x 11 x 1 inches.

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