This fluffy buttercream has real marshmallows mixed right into the frosting. It is relatively stable, super delicious and lots of fun.
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.
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!
Marshmallow Buttercream Frosting with Mini Marshmallows
- 16 oz mini marshmallows
- 3 Tablespoons milk and more as needed
- 1 cup unsalted butter soft
- 1 cup shortening
- 4 cups powdered sugar
- 1½ teaspoons vanilla extract
- ¼ teaspoon salt
- 2 Tablespoons meringue powder optional
- 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.16 oz mini marshmallows, 3 Tablespoons milk
- Meanwhile beat the butter until it is smooth and creamy. Add the shortening and beat until combined.1 cup unsalted butter, 1 cup shortening
- Add melted marshmallow mixture and mix well.
- Stir in powdered sugar, salt, meringue powder and vanilla. Mix on low for several minutes.4 cups powdered sugar, 1½ teaspoons vanilla extract, ¼ teaspoon salt, 2 Tablespoons meringue powder
- Adjust the consistency with more milk or powdered sugar as needed.