crusting marshmallow buttercream for sugar cookie decorating

The Easiest Marshmallow Buttercream for Sugar Cookie Decorating

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Marshmallow buttercream brings back childhood memories of eating s’mores, marshmallow candies, and even just plain ol’ good marshmallows.

Marshmallow is definitely a nostalgic flavor for many.

This marshmallow buttercream brings the nostalgia and is absolutely perfect for decorating sugar cookies.

It’s just the right texture, not too thick, not sticky at all, and it crusts!

If you’re unfamiliar with the term crusting buttercream, all that means is that the outermost layer will form a slight crust, helping to protect the design.

Plus, a bonus to using a crusting marshmallow buttercream means that it is shelf stable for a few days! The high sugar to fat ratio acts as a preservative. Cool, huh?

Marshmallow buttercream goes exceptionally well with vanilla, chocolate fudge, and s’mores cut out sugar cookies

Follow along for the marshmallow buttercream recipe that’s so easy, you’ll wonder why you haven’t made it before!

*This post may contain affiliate links, which means I may receive a commission, at no extra cost to you, if you make a purchase through a link. Please see my full disclosure for further information.*

How to Make The Easiest Marshmallow Buttercream

Picking the Right “Type” of Marshmallow

The first step toward making this super easy marshmallow buttercream is to obtain one simple ingredient: marshmallow flavor.

Marshmallow Flavor Lorann

Trying to add marshmallow fluff or cream will alter the buttercream consistency. This is fine for frosting a cake and even cupcakes, but cookies need a crusting buttercream.

The marshmallow flavor super concentrated which means you won’t need to add much at all.

You will only need to use one half teaspoon of marshmallow flavor in the recipe. This will not mess up the sugar to butter to liquid ratio needed to obtain a nice crusting buttercream.

Ingredients to Gather to Make Marshmallow Buttercream

American buttercream contains just a handful of ingredients:

Making the Crusting Marshmallow Buttercream Frosting

In a stand mixer with the paddle attachment, whip one cup of room temperature unsalted butter until light and fluffy. One cup of butter is equivalent to two sticks of butter or 16 tablespoons.

Once light and fluffy and all of the lumps are gone, mix in four cups of powdered confectioner’s sugar, one half teaspoon of marshmallow flavor, one tablespoon of whole milk or cream, and one and a half teaspoons of vanilla extract.

Remember, we use four cups of powdered sugar in order for the frosting to form a slight crust. If you don’t need a crusting buttercream (i.e. you’re not decorating sugar cookies with it) you can put less sugar in to taste.

Mix everything on low speed until the powdered sugar is mixed in to the butter completely. Do not turn the mixer higher than low. If needed, use a rubber spatula to stir the frosting.

Overmixing buttercream can cause air bubbles. If you do overmix, here’s a post on how to fix it. I promise it’s not terribly hard to fix, but, as always, prevention is better.

If the marshmallow buttercream is too thick, add more milk, up to four tablespoons, until the desired consistency is reached. I like a creamy peanut butter consistency.

Once the frosting is mixed, place it into a piping bag with your preferred decorating tip and decorate.

easy marshmallow buttercream

If you aren’t ready to decorate, keep the buttercream in an airtight container in the refrigerator for up to a week or the freezer for up to three months.

How to Decorate Cookies with Marshmallow Buttercream

marshmallow buttercream on buttercream sugar cookies

As mentioned, this marshmallow buttercream is a crusting buttercream so you can decorate sugar cookies in the same way you’d decorate with regular crusting buttercream.

If you need some ideas, make sure to hop around this blog, there’s over 150 cookie tutorials on here for free!

Royal icing versus buttercream frosting, which is better for cookie decorating

Check the menu at the top of the page or even the homepage,

I decided to decorate some s’mores cut out sugar cookies with this marshmallow buttercream.

Here are the easy instructions for decorating:

  1. Place a cup of marshmallow buttercream into an icing bag with a Wilton tip #1M.
  2. Start in the center of the cookie and make a swirl around it to create a rosette.

If you’re new to rosettes, I have a whole blog post dedicated to how to pipe buttercream rosettes.

Since I decorated s’mores cut out sugar cookies with the marshmallow buttercream, I added some mini marshmallows, chocolate chips, and Christmas sprinkles on top. I brought these to a couple Christmas parties.

marshmallow buttercream on smores sugar cookies

Make sure to check out my other crusting buttercream recipes!

crusting marshmallow buttercream for sugar cookie decorating

The Easiest Marshmallow Buttercream Recipe for Sugar Cookie Decorating

You'll love this marshmallow buttercream frosting recipe that works perfectly for cookie decorating, icing cakes, and topping cupcakes.
Print Pin Rate
Course: Dessert
Cuisine: American
Keyword: All American Buttercream Frosting, Crusting Buttercream, Marshmallow Buttercream
Prep Time: 1 hour
Mixing Time: 5 minutes
Total Time: 1 hour 5 minutes
Author: Leah Buehler


  • Stand Mixer with Paddle Attachment
  • Rubber Spatula
  • Measuring cups and spoons


  • 1 cup unsalted butter room temperature
  • 4 cups powdered sugar
  • ½ tsp. marshmallow flavor
  • 1 ½ tsp. vanilla extract
  • 1-4 tbsp. whole milk or cream


  • In a stand mixer with the paddle attachment, beat the room temperature butter until soft and fluffy.
  • To the stand mixer, add the powdered sugar, marshmallow flavor, vanilla extract, and one tablespoon of milk or cream and mix on low speed until fully incorporated.


You can add 1-4 tablespoons of milk or cream into the marshmallow buttercream recipe, this will depend on the consistency you want for your piping. I prefer a smooth peanut butter consistency.
For a non-crusting buttercream, reduce the sugar to 2-3 cups, depending on your taste preference. If you are needing a crusting buttercream, do not reduce the amount of sugar, as this is what makes it form a crust.
This marshmallow buttercream tastes amazing on my s'mores cut out sugar cookie recipe

Save the Recipe for Marshmallow Buttercream

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the easiest crusting marshmallow buttercream

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