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When I want people to beg me for a recipe for cake, this is what I make. My creamy, sweet Marshmallow Frosting made with marshmallow fluff and butter is great on top of any type of cake, cookie or cupcake. It comes together in just minutes with a hand mixer.

Close up photo of white swirled marshmallow frosting on a chocolate cupcake.

Yes, this cupcake icing is sticky, but it is so worth it! It has an unforgettable butter flavor that people wonโ€™t stop talking about. Itโ€™s the perfect blend of marshmallows and butter, and it belongs on almost everything.

This recipe starts with a jar of marshmallow fluff, which is not the same as marshmallows, by the way! I can barely keep it in my pantry, because I love to use it in so many recipes. If you happen to come across a jar of strawberry fluff, make my strawberry rice krispies treats. If plain is all you can find, donโ€™t miss my fruit dip made with fresh strawberries.

Words almost can not express the deliciousness that is this recipe! There is something magical that happens when sweet, sticky marshmallows collie with butter and a big hit of salt. Itโ€™s salty sweet perfection in a bowl or on a cupcake!

Group of 3 cupcakes with swirled buttercream on top and pastry bag on side.

Marshmallow Frosting Recipe Ingredients

Ok, I trust that you can find many ways to use this delicious marshmallow frosting, so letโ€™s talk about the ingredients.

Photo of marshmallow fluff, butter, powdered sugar, salt and vanilla on grey counter.
  • Butter. This recipe makes enough frosting for 1 dozen cupcakes, so we need one and a half sticks of unsalted butter that has been softened to room temperature. The best way to soften butter is to open the package, slice it into tablespoon-size chunks, and let it rest. When you can easily make a fingerprint in the butter, itโ€™s ready to use. However, make sure itโ€™s not overly melty.
  • Powdered Sugar. Because marshmallow fluff already contains sugar, we just need one cup of powdered sugar.
  • Vanilla Extract. An extra dose of vanilla amps up the flavor here.
  • Salt. Please donโ€™t skip the salt. We need one-half teaspoon of fine sea salt to dissolve in the bowl. It really balances all the sweetness, so please donโ€™t skip it. Also, please donโ€™t use coarse or large-grained sea salt, as it might not dissolve properly.
  • Marshmallow Fluff. One 7-ounce jar of marshmallow fluff in the classic, white plain flavor. If youโ€™re lucky enough to find other flavors of it, experiment and enjoy!
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How to Make Marshmallow Frosting

Softened butter beaten in a white mixing bowl.
Powdered sugar added to a bowl of beaten butter in white mixing bowl.
  1. In a large bowl, add the butter. Beat with an electric mixer on high speed until light and fluffy, at least 2 minutes. It will go from bright yellow to a more pale yellow color after beating.ย 
  1. Continue beating and add the powdered sugar a little at a time until fully incorporated.ย 
Drops of vanilla and salt in a yellow frosting in white mixing bowl.
Jar or marshmallow fluff going into bowl of marshmallow frosting.
  1. Add the salt and vanilla and beat for another minute to fully dissolve the salt.
  1. Finally, scrape the contents of the marshmallow fluff from the jar into the bowl as best as you can. Itโ€™s super sticky!
Homemade marshmallow frosting in white mixing bowl, smooth on top.
Piping bag putting icing on chocolate cupcake from above.
  1. Beat everything together until nice and fluffy, and the frosting is no longer sticky. It should be fluffy and spreadable.
  1. If your marshmallow frosting is still too sticky or runny, beat it longer! After another 3-4 minutes, if itโ€™s still not the right texture, refrigerate it for 30 minutes and beat it again.
Brown cupcake, white frosting, decorated with pink and white baubles.

How to Store Marshmallow Cake Frosting

Almost always, leftover food is meant to be stored in the fridge. This is because cold temperatures prevent bacteria growth. So, after making this recipe, store it in the fridge and simply let it rest at room temperature for a few minutes before serving to soften. Any leftovers can go in the freezer for up to 3 months. Defrost overnight on the counter and then re-whip before using.

Does marshmallow frosting need to be refrigerated?

Because this recipe contains dairy in the form of butter, it is really meant to be stored in the fridge. However, the butter will cause it to harden slightly, so simply remove it from the fridge for about 20 minutes before serving. Letโ€™s practice good food safety, ok?

Marshmallow Cream Frosting FAQs

Why is my marshmallow frosting runny?

If your results are runny, I urge you to just keep mixing. Turn your electric hand mixer to high speed, and keep whipping it until it stiffens up. If that doesnโ€™t work, place the bowl in the fridge for 30 minutes, and then beat again. I donโ€™t recommend adding more powdered sugar to stiffen it up, as sugar is a liquid ingredient and dissolves and makes things runnier. Using a colder temperature is the best way to achieve great results with any type of frosting that contains butter.

Can you use melted marshmallows instead of marshmallow fluff?

So, marshmallow fluff isnโ€™t just a jar of melted marshmallows. It contains slightly more corn syrup to make it smoother and spreadable. If you want to create marshmallow fluff from marshmallows, melt the marshmallows over very low heat. When the marshmallows are melting and still a bit lumpy, stir in light corn syrup slowly until the mixture fully melts and becomes white and creamy. Remove from heat and let cool before using in your recipe.

Why is my marshmallow frosting grainy?

Grainy marshmallow frosting occurs when you make the marshmallow fluff from scratch, with egg whites and granulated sugar. The graininess is actual grains of sugar that did not dissolve in the heating process. However, my recipe for marshmallow frosting starts with a jar of marshmallow fluff to prevent this!

Ways to use Marshmallow Fluff Frosting

Yield: 2 cups

Marshmallow Fluff Frosting

Close up photo of white swirled marshmallow frosting on a chocolate cupcake.

Fluffy, creamy marshmallow frosting made with marshmallow fluff. Recipe makes enough to frost 1 dozen cupcakes.

Prep Time 15 minutes
Total Time 15 minutes

Ingredients

  • 1 1/2 sticks of unsalted butter
  • 1 cup powdered sugar
  • 1 teaspoon vanilla extract
  • 1/2 teaspoon fine sea salt
  • 7 ounce jar of marshmallow fluff

Instructions

  1. In a large bowl, add the butter. Beat with an electric mixer on HIGH speed until light and fluffy, at least 2 minutes. It will go from bright yellow to a more pale yellow after beating.
  2. Continue beating and add the powdered sugar a little at a time until fully incorporated.
  3. Add the salt and vanilla and beat for another minute to fully dissolve the salt.
  4. Finally, scrape the contents of the marshmallow fluff from the jar into the bowl as best as you can. Itโ€™s super sticky! Beat everything together until nice and fluffy, and the frosting is no longer sticky. It should be fluffy and spreadable. See tips below if overly sticky or runny.

Notes

If it's runny, keep beating. Turn your electric hand mixer to high speed, and keep whipping it until it stiffens up. If that doesn't work, place the bowl in the fridge for 30 minutes, and then beat again. I don't recommend adding more powdered sugar to stiffen it up, as sugar is a liquid ingredient and dissolves and makes things runnier. Temperature change is the best way to achieve results with any type of buttercream.

Nutrition Information:

Yield:

6

Serving Size:

1

Amount Per Serving: Calories: 381Total Fat: 23gSaturated Fat: 14gTrans Fat: 0gUnsaturated Fat: 8gCholesterol: 61mgSodium: 206mgCarbohydrates: 45gFiber: 0gSugar: 37gProtein: 1g

Did you make this recipe?

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About Christina Lane

Christina Lane is the author of 5 cookbooks all about cooking and baking for two. She has scaled down hundreds of recipes into smaller servings so you can enjoy your favorite dishes without the leftovers! Valentine's Day is her favorite holiday.

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7 Comments

  1. Katie says:

    Hello! Sounds like a frosting my daughter would love! Iโ€™m wondering if youโ€™ve ever tried tinting it for decorating? Thank you!

  2. Kim says:

    Hi! Excited to try this recipe, but do you think you could include how many cups/grams are in โ€œsticksโ€ of butter? I am Canadian and had no idea this was an American unit of measurement.

    Happy Holidays!

    1. KimminyCricket says:

      Hi, Kim,

      Your question was so long ago โ€” maybe youโ€™ve gotten your answer by now(?). One stick of butter is 8 tablespoons, or 1/2 cup, or 4 ounces.
      There are online measuring charts available for converting units of measurement like cups, teaspoons, tablespoons, etc.
      Hope this helps.
      *From a fellow Kim*

  3. Deborah says:

    Wow! The marshmallow frosting is next level and a fabulous change to buttercream. Please could you update with metric weight for all ingredients. Iโ€™m so keen to make a batch. Thank you. ๐Ÿฅฐ๐Ÿ’•๐Ÿง

  4. Bernadette Novak says:

    Hi. Can I use this frosting to put into a layer cake. Not sure if it would melt if I am putting it in between the cake layers. Thanks.

    1. Christina Lane says:

      You can, keep it cold and store in the fridge:)

  5. Bee says:

    Would this work well inside or covering an ice cream cake?