Marshmallow Fondant

Course: Dessert
Cuisine: American
Keyword: chocolate cake, homemade cake, marshmallow fondant
Dessert Type: Misc. Desserts
Prep Time: 10 minutes
Cook Time: 5 minutes
Total Time: 15 minutes
Servings: 1 lbs
Calories: 1657kcal
Author: Elizabeth LaBau
This Three-Tier Chocolate Celebration Cake is absolutely delicious with its deep devil food chocolate, fresh strawberry Swiss meringue buttercream and chunks of fresh strawberries throughout! My mouth is watering just thinking about it!
Print Recipe


  • 8 ounces miniature marshmallows 4 cups not packed, or half of a 16-ounce bag
  • 2 tbsp water
  • 1 pound powdered sugar 4 cups, plus extra for dusting


  • In a large microwave-safe bowl, combine the marshmallows and water. Microwave them together for 1 minute, then stir with a rubber spatula until they are melted and smooth. If some unmelted marshmallow pieces remain, return to the microwave for 30-45 seconds, until the marshmallow mixture is entirely smooth and free of lumps.
  • Add the powdered sugar all at once to the bowl, and stir it in. It will be very sticky, and may seem way too dry at first. Continue to stir until it’s too sticky and difficult to stir. Dust your work surface with powdered sugar, and turn the marshmallow/sugar mixture out onto the work surface. There will be a lot of excess sugar, and the marshmallow mixture will look rough and shaggy.
  • Start to knead everything together, dusting your hands generously with sugar whenever they start to get sticky. As you knead, the fondant will gradually start to take in more and more of the sugar and will smooth out and become less sticky. Continue to knead the fondant until it smoothes out and loses its stickiness. Add more sugar if necessary, but stop adding sugar once it is smooth--too much sugar will make it stiff and difficult to work with. Once the fondant is a smooth ball, it is ready. Wrap it well with cling wrap and store it in an airtight container at cool room temperature.
  • I prefer to make my fondant the day before I need it, and to let it sit overnight to firm up a bit. If well-wrapped, fondant can be made up to several weeks in advance. It will need to be kneaded until supple before later use.

To Assemble the Cake:

  • Supplies:
  • 10" cardboard cake rounds
  • 6" cardboard cake rounds
  • 4” cardboard cake rounds (hard to find, you can cut larger ones down to size)
  • Dowels—I like to use boba tea straws
  • Pastry bag
  • Pastry tips
  • Cake turntable (optional but makes decorating easier)
  • Bench scraper
  • Offset spatula
  • 2 lbs strawberries, washed, hulled, and coarsely chopped
  • Assemble the 10” tier first. Using a large serrated knife, cut each cake layer in half. Place one layer face-up on a cake cardboard.
  • Scoop some buttercream into a pastry bag fitted with a 1/2-inch round tip. Pipe a ring of buttercream all along the edge of the cake round to act as a barrier and make assembly neater. Scoop about 2/3 cup buttercream into the center, and spread it in an even layer until it covers the cake and reaches the buttercream ring. Scatter a generous handful of chopped strawberries on top, covering the surface evenly, but do not put strawberries on the outer ring of buttercream. Top the cake round with a second round, and repeat the process of piping a ring of buttercream, spreading the buttercream in the center, and add chopped strawberries.
  • Repeat with the remaining layers, until you have a 4-layer cake with 3 layers of buttercream. Spread buttercream along the sides and top of the cake in a very, very thin layer—this is just to hold the crumbs in. Refrigerate the layer while you assemble the 6” and 4” rounds in the same fashion. Refrigerate all the layers until they’re firm, at least 45 minutes.
  • Once firm, go back and add another layer of buttercream on the outside of the cakes, this time trying to get it even and smooth. The smoother the buttercream is, the smoother the fondant coating will be. I like to use a bench scraper to go around the sides and get them very straight and clean. To do this, hold the bench scraper in your dominant hand, straight against the sides of the cake. With your other hand turn the cake turntable so the scraper removes any excess frosting from the sides. Use an offset spatula to smooth the frosting on the top of the cake. Once all of the cakes are frosted, refrigerate them again until they’re very firm, at least 1 hour or more for the larger cakes.
  • To cover the cakes with fondant, I used these approximate amounts:
  • 10” cake: about 2 1/4 lbs fondant
  • 6” cake: about 1 lb fondant
  • 4” cake: about 12 oz fondant
  • Dust your work surface with powdered sugar, and roll out the fondant until it is a round a little less than 1/4-inch thick. Drape it over the cake and smooth it evenly against the top and sides—if you are unfamiliar with covering a cake with fondant, there are many excellent video tutorials to demonstrate this step. Trim the excess fondant from the bottom, and refrigerate the cakes until you’re ready to decorate and stack them.
  • Use excess fondant to make decorations of your choice. Glue them on with Tylose glue (preferred) or corn syrup.
  • To stack the rounds, insert a boba tea straw (or other type of dowel) into the center of the 10” cake. Hold scissors flush against the top of the cake, and cut off the top of the straw so that it is now even with the height of the cake. Add four more straws in a circle around the straw in the center, each about 2” from the center (so that they don’t extend past a 6” radius) and cut those straws so that their height is the same as the cake. These straws will be used to support the 6” cake. Smear a generous amount of buttercream in the center of the 10” cake, and put the 6” cake on top, so it’s secured by the buttercream and resting on the dowels. There should be no gap between the cakes.
  • Insert two straws, about an inch apart, in the center of the 6” cake, and cut off the tops. Smear some buttercream on the 6” cake to secure the 4” one, and place it on top. Finish your cake by piping buttercream or tying ribbon around the bottom of the cakes to make them look polished.


Calories: 1657kcal | Carbohydrates: 424g | Protein: 2g | Sodium: 128mg | Sugar: 382g | Iron: 0.5mg