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Marshmallow Buttercream Frosting with Mini Marshmallows

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This fluffy buttercream has real marshmallows mixed right into the frosting. It is relatively stable, super delicious and lots of fun.

Piped swirl of fluffy white marshmallow buttercream frosting.

Picking a frosting to finish of a cake or batch of cupcakes is a big decision. There are so many varieties and flavors to choose from!

Little Dude requested a chocolate and vanilla cake for his birthday. So we ended up making a four layer cake with alternating layers of chocolate and funfetti cakes.

We knew we were going to be making building blocks out of marshmallow fondant. It was the perfect way to decorate a cake for his lego party.

Small cake frosted with marshmallow buttercream and decorated with fondant blocks.

Because of the colorful decorations, we wanted a bright white background. It would have been easy to just make American buttercream or a slight twist on that like sweetened condensed milk buttercream.

But the marshmallow fondant had me in the mood for more marshmallow goodness, so marshmallow fluff buttercream seemed like the perfect base. The only problem was I didn’t have any marshmallow fluff.

I did, however, have some extra marshmallows on hand. The first batch made more blocks than we expected, so we didn’t need to make more like we had anticipated.

So I made buttercream out of marshmallows instead! And you know what? It was delicious!

Getting your frosting ready

If you are going to have a buttercream built on marshmallows, you have to melt those marshmallows. I find the easiest way is to use a large glass bowl in the microwave.

Start with about a minute and then use short bursts until the marshmallows can be stirred smooth. Add a little milk to loosen them up.

Beat some butter until it is smooth and creamy. Now add the melted marshmallows and mix well.

It should make a smooth glossy mixture. Some slight stringing is ok.

If you happen to have some meringue powder, go ahead and add some in. The marshmallows and meringue powder will help to add some stability to your final buttercream.

If you don’t have the meringue powder, don’t despair. The frosting will still work without it.

A little powdered sugar, vanill and more milk is all it takes to finish off the recipe. Adjust with a little more milk or powdered sugar to get you desired consistency.

I personally prefer a softer frosting for spreading and a tighter frosting for piping. It’s easy to adjust to your liking.

Decorating your cake

To make the cake, I piled plenty of frosting between the layers. Even at the looser consistency, it held its own under the weight of the top layers.

The crumb coat went on easily as well. After a quick chill to set the crumb coat, we lathered on the final coat.

It smoothed out nicely and was plenty sticky for Little Dude to arrange his lego blocks wherever he wanted. We also did a little cake just for him!

That way he could blow out his candle without blowing on the whole cake. We jokingly called it his smash cake and he took it seriously.

He ended up eating it with his face. It was funny even if it was messy!

Boy putting his face into a cake.
Yield: 36 Servings

Marshmallow Buttercream Frosting with Mini Marshmallows

Piped swirl of fluffy white marshmallow buttercream frosting.

This fluffy buttercream has real marshmallows mixed right into the frosting. It is relatively stable, super delicious and lots of fun.

Prep Time 12 minutes
Cook Time 5 minutes
Total Time 17 minutes

Ingredients

  • 16 oz mini marshmallows
  • 3 Tablespoons milk (and more as needed)
  • 1 cup butter, soft
  • 1 cup shortening
  • 4 cups powdered sugar
  • 1/4 teaspoon salt
  • 2 Tablespoons meringue powder (optional)

Instructions

  1. Melt marshmallows in large microwave safe bowl in 30 second bursts until it can be stirred smooth. Stir in milk, set aside to cool a bit.
  2. Meanwhile beat the butter until it is smooth and creamy. Add the shortening and beat until combined.
  3. Add melted marshmallow mixture and mix well.
  4. Stir in powdered sugar, salt, meringue powder and vanilla. Mix on low for several minutes.
  5. Adjust the consistency with more milk or powdered sugar as needed.

Nutrition Information:

Yield:

36

Serving Size:

1

Amount Per Serving: Calories: 187Total Fat: 11gSaturated Fat: 6gTrans Fat: 0gUnsaturated Fat: 5gCholesterol: 17mgSodium: 67mgCarbohydrates: 23gFiber: 0gSugar: 20gProtein: 0g

All nutritional information is estimated and will depend on the exact ingredients you use.

Did you make this recipe?

I'd love to see it! Share a picture on Instagram or Pinterest and tag me @carleecooks to let me know how it went!

This fluffy buttercream has real marshmallows mixed right into the frosting. It is relatively stable, super delicious and lots of fun.

Share with your friends!

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Shannon

Monday 31st of May 2021

My daughters would love this! Pinning for future reference.

Carlee

Monday 31st of May 2021

I hope you all love it!

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