Marshmallow Fondant & The Worlds Best Birthday Cake.

Last year, when it came time to celebrate our Childs first full trip around the sun, my wife and I decided to start a new tradition in our home. Each year whenever our children’s birthdays come around (one day we’ll have more than just the one) we would make their birthday cake ourselves. As they grow older we hope to include our children in this tradition, helping make the day special for those who aren’t celebrating as they help to create a beautiful memory for their sibling. In the long term, the goal will be for one parent to distract the birthday child, while the other parent helps create a special birthday cake with their siblings. For the moment we just make the cake while our kid sleeps, but it’s nice to know we have a plan.

I’m sure one day we’ll buy a cake for someones birthday, but I absolutely love baking at home and so does my wife. What we really want to instill in our kids is the joy that comes from making something by hand and being given something hand made. That sometimes rough edges make a better story, and there is real value in knowing how to make something delicious for yourself and others.

For last year’s cake, my wife created an absolutely beautiful homage to Cookie Monster, with bright blue butter cream, goggly eyes, and mini cookies for decoration. This year, for their second birthday, I wanted to try my hand at something new and adventurous, marshmallow fondant.

The Great British Baking Show has been a mainstay in our home for quite some time, and even though I’ve always admired fondant work I’ve never gotten up the courage to attempt it myself. As a young cook I was blessed to learn from one of the best pastry chefs on the East Coast. I was employed as a line-cook in a high end restaurant in DC and the Husband and Wife Chef team handled both the savory and pastry sides of business. During my time their, I would often spend extra minutes trying to glean as much info as I could from the pastry sous chefs and assistants. As time went on, the pastry chef would show me things and eventually let me work occasionally as a pastry assistant in the commissary kitchen that created desserts for the entire restaurant group. So while I’m not a newb at baking/pastry, I had never heard of marshmallow fondant until watching The Great British Baking Show.

Once I understood the process however, I was struck by how simple and utilitarian a marshmallow fondant could be. First of all it is incredibly inexpensive to make, and furthermore, it actually tastes better IMO than traditional store bought fondant. While cake decorating never really interested me as a younger cook, my desire to create an amazing birthday cake for my kid had me ready to roll up my sleeves and get to work.

Even though it was my first attempt at fondant work, and it was filled with missteps and valuable learning moments, it was still a lot of fun. I would recommend this process to anyone who is interested in expanding their cake skills, and is willing to waste a bag of marshmallows to see what fondant is actually like.

One important note before diving into this recipe. This method calls for the use of a counter top stand mixer to help create the fondant. If you don’t have one available to you, make sure to google “marshmallow fondant by hand” before attempting this recipe. Making fondant by hand can be frustrating and it is best to give the process an overview before diving in and making a gigantic mess.

Marshmallow Fondant & The Worlds Best Birthday Cake.

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Recipe by Paul Kostandin Course: DessertDifficulty: Medium


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This super easy marshmallow fondant recipe will really step up your cake game to the next level. The best part is it’s super easy to make and way less expensive than traditional store bought fondant!


  • For the cake
  • 1 cup canola or vegetable oil

  • 1.5 cups granulated sugar

  • 4 each large eggs

  • 1.5 cups whole milk

  • 2 tsp baking powder

  • 3 cups all purpose flour

  • 1 tsp salt

  • 1/4 cup rainbow sprinkles

  • For the buttercream
  • 8 oz softened butter

  • 1/4 cup milk

  • 2 lbs powdered sugar

  • 1/2 tsp salt

  • 1 tsp vanilla extract

  • For the fondant
  • 1 lb mini marshmallows (1 regular sized package)

  • 1 oz water

  • 2 lbs powdered sugar

  • Food Coloring


  • To make the cake
  • Preheat your oven to 350°F.
  • In a stand mixer combine the sugar, eggs and vegetable oil.
  • Mix on medium speed with the whisk attachment until the mixture is light and fluffy.
  • Add the milk to the mixer along with the flour, salt, and baking powder.
  • Continue to mix on low speed until all the ingredients are combined and you have achieved a smooth, even batter.
  • Add the rainbow sprinkles to the batter and continue mixing on low speed for another 30 seconds until the sprinkles are just combined.
  • Divide the cake batter evenly between 2 greased, 9′ cake pans.
  • Place the cake pans on the middle rack of your preheated oven and allow them to bake for 25 minutes or until they are golden brown and a cake tester comes out cleanly.
  • Place the cakes on a cooling rack and allow them to cool fully before removing them from their pans.
  • Place the cakes in the freezer for 1 hour before decorating.
  • To make the buttercream.
  • Place the softened butter into a stand mixer with a whisk attachment and begin to mix on medium/low speed.
  • Once the butter has begun to gain volume and grow pliable, slowly stream the milk into the mixing butter.
  • Once the milk is incorporated, increase the speed to high and continue to mix until the butter is light and fluffy.
  • Working 1 cup at a time add the sifted confectioners sugar to the butter. You will need to reduce the speed to low/medium to allow the sugar to incorporate without making a mess.
  • Once all the sugar is incorporated increase the speed to high once more and continue to mix until the buttercream is light and fluffy. The volume should be about double the original starting volume.
  • Reserve the buttercream until decorating.
  • To make the marshmallow fondant.
  • Place the marshmallows in a microwave safe bowl and begin to microwave them for 30 second intervals.
  • Remove the bowl and mix the marshmallows with a rubber spatula between every interval.
  • After 2-3 minutes the marshmallows should be completely melted and fully liquid.
  • Transfer the melted marshmallows to a stand mixer bowl with the dough hook attachment. Begin to mix on low speed.
  • Working a cup at a time add the sifted powdered sugar to the marshmallow mixture and allow it to fully incorporate before adding the next cup.
  • Add the water to the mixing fondant in between sugar additions. Add a little bit as you need to make sure the fondant remains workable but not sticky.
  • A this point you can add food coloring as you desire to to the fondant. For this recipe I colored a larger portion of the fondant bright yellow and then mixing a smaller portion by hand with a blue coloring to achieve a marbles look for the accents.
  • Reserve the fondant wrapped tightly in platic wrap until ready to decorate the cake.
  • To assemble and decorate.
  • Trim your cakes so that sit level.
  • Place one cake round on a cake board and apply a finger width layer of icing to the top of the cake.
  • Place the second cake layer on top of the icing.
  • Apply the remaining buttercream to the outside of the cake creating a 1/4 inch thick layer of icing all the way around.
  • Use an offset spatula to smooth and level the icing.
  • Measure the height of the cake and the width of the cake with icing. Multiply the height of the cake by 2 and add it to the width of the cake. This is the total diameter you need to roll your fondant to adequately cover your finished cake. This batch of fondant will more than cover a 9 inch cake but it’s nice to know exactly how big you’ll need to be rolling your fondant.
  • Roll your fondant out on a fondant mat or use cornstarch to help keep your fondant from sticking to a countertop.
  • I like to aim for a 1/4 inch thickness on my fondant layer, once your fondant has achieved the proper thickness and diameter roll it up over the rolling pin so the fondant is loosely rolled completely around the pin.
  • Carefully drape the fondant over the iced cake, unrolling the fondant as you go to completely cover the cake.
  • Using a fondant smoother or the back of a wooden spoon, manipulate the fondant down the cake, smoothing any wrinkles or air pockets as you go.
  • Cut the excess fondant away from the bottom of the cake and tuck the remaining edge against and under the cake.
  • At this point you can roll out and apply any accents you wish, or you can serve the cake as is with a classic, delicious layer of fondant.


  • Applying fondant is best explained via demonstration and the fine folks at Wilton have a far better job than I ever could in explaining how best to apply an even layer of fondant. Check out the video here!

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