EATS / Kids Birthday Recipes

Marshmallow Creme Slime Party Cake


Are your kids as completely obsessed with slime as mine are? We found a way to make edible slime with the sweetest taste using homemade marshmallow creme – It’s a slime cake! A marshmallow cream cake that mimics their favorite gooey fun. This cake is so fun for a slime party. My kids have already been asking if they can have a slime birthday party next year.

Marshmallow Creme

I LOVE THE CURRENT SLIME TREND. :) Slime, sticky, ooey gooey slime!!! It was one of my favorite things as a kid, and just one of those nostalgic things that sticks around. And now it is all my kids want to do. The only problem is, you can’t eat it, ha ha!!! But, of course, we found a way. There is always a way! Just like when we created edible glitter or showed you how to create edible balloons to top your cake.

It wasn’t easy, but here it is, an marshmallow creme edible slime cake, YAY!!!

Slime party cake

marshmallow cream recipe

Make Your Own Slime Cake With Homemade Marshmallow Creme

To make your own slime cake for an epic slime party, you will need:

  • 4 layers of your favorite cake, you can use your favorite box or homemade recipe
  • 8” round cake pans
  • 4” circle cookie cutter
  • 1 recipe for marshmallow creme, recipe below
  • Gel Food Colors
  • Your favorite vanilla buttercream recipe, store bought is fine too
  • Candy Melts

A slime cake for a slime birthday party

Slime Party Cake

1. To make the slime party cake, bake your 8” round cakes. I made 4 layers of colorful marble cakes by coloring my vanilla cake batter pink, blue & purple and swirling them together in the pan before baking.

2. Once cakes have cooled completely trim any caramelization off and level your cakes.

3. Take 2 of your layers and cut a hole in the center using your 4” round cookie cutter.

4. Set layers aside and make your marshmallow creme “slime” and buttercream (if you didn’t use store bought).

Marshmallow Cream Recipe

Marshmallow Creme Recipe

To make the best marshmallow creme recipe you will need:

1. To make the marshmallow cream, start with a stand mixer fitted with the whisk attachment, add your egg whites and cream of tartar and begin to mix on low speed. Increase speed to medium, until soft peaks begin to form.

2. While your egg whites are whipping, in a medium saucepan over medium heat add your sugar, water, salt and vanilla extract and heat mixture until it reaches 230 degrees F on a candy thermometer.

3. Remove sugar mixture from heat, allowing it to heat to 240 degrees F before adding it to your whipped eggs whites. This makes for the fluffiest marshmallow creme around! It is really almost as good as slime.

4. With your mixer on medium, slowly add your syrup to the mixture. Make sure not to add it too quickly, you want to avoid getting chunky egg whites in your slime, eww!

5. Once all of your sugar syrup is combined, increase mixing speed to high and mix until slime has doubled in volume.

6. Add green gel food coloring to get your slimy green color.

7. Set aside and assemble your slime party cake.

How to make marshmallow creme

Slime Cake Assembly

1. Place your bottom layer of cake on a cake board and add a thin layer of your buttercream.

2. Add one of your rings of cake and another layer of buttercream to the ring. Do the same thing with the second ring.

3. Fill the middle of your cake with your marshmallow creme slime and top with another layer of buttercream. You don’t have to cover the top of the slime with buttercream if you don’t want to.

4. Add your final layer of cake and crumb coat the entire cake, placing it in the fridge for 10 minutes when you’re done.

Slime party ideas

5. Remove cake from fridge and give it another coat of buttercream and place back in the fridge for a few minutes

6. Melt your candy melts and allow to cool for a little bit before pouring on your cake

7. Since this was a slime cake I thought it’d be fun to get a little messy with the candy melts, giving more of slime look and not that “perfect” dripped cake look. So don’t worry if your drips aren’t perfect

8. After the candy melts set, I finished the cake with a few buttercream rosettes and a little disco dust for a final touch
This cake turned out pretty cute on its own, but cutting in to it was even more fun. Not only were the colorful marble layers a fun surprise, but the marshmallow creme oozes out exactly like slime would, making this the best slime I’ve ever played with!!! I love how colorful it was and if you really want to, you could make an extra recipe of marshmallow creme and have a good ‘ole time playing it.

PS. If you’re planning to have a slime party, make sure to use our tutorial on how to make slime without borax to hand out as favors, or even make together as a craft!

(Project recipe, styling, and photography @A Subtle Revelry by Brandi Van Leer.)


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  • Barbara
    May 12, 2018 at 8:50 am

    Will the slime ooze out if I made this cake a day ahead of time? Will it be safe unrefridgerated over night?

    • Kat
      June 27, 2018 at 6:13 am

      I am wondering the same!

      • Victoria
        June 27, 2018 at 6:25 am

        Hi! It should keep for up to 3 days covered and stored. The “slime” is thick enough that it will stay in place until the cake is cut. Hope that helps!

        • Kat
          June 28, 2018 at 2:31 pm

          Thank you!!! Making as we speak!!!

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  • Ruth A
    July 17, 2018 at 11:41 am

    1/2…. What… Cotton Candy Extract. Do you know if I can get this at Michael’s?

    • Victoria
      September 21, 2018 at 8:52 am

      Amazon has it if not!

  • Irene
    September 20, 2018 at 4:52 pm

    Can you do this with marshmallow creme to save time?

    • Victoria
      September 21, 2018 at 8:52 am

      Possibly! I don’t see why that wouldn’t work. I’d love to see it when you try it out.

  • Natasha
    January 24, 2019 at 5:59 pm

    Cotton candy extract…is that just a flavour? Can I sub with vanilla extract?

    • Victoria
      January 25, 2019 at 6:19 am

      It is a flavor we love in this recipe, but Vanilla would work as well!

  • Beverly Hunsuckle
    February 12, 2019 at 2:34 am

    1/2 of what? You don’t tell how much of the cotton candy extract and where does the syrup come from it’s not in the recipe

    • Victoria
      February 12, 2019 at 6:23 am

      1/2 tsp. Just realized that and fixed it! Sorry. The cotton candy extract can be purchased on Amazon, I’ve linked it above. Or try vanilla – many comments above have subbed that in.

      • beverly hunsuckle
        February 12, 2019 at 1:49 pm

        Thank you and I am going to try the vanilla because I have looked all over for the other and I have to make this cake by Friday so Im going to try it out

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