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Lucky Charms Cereal Cake

The famous Lucky Charms marshmallows are decorating the outside of the cake and a whimsical white chocolate milk spill topping the cake. This cake is perfect for celebrating St. Patrick’s Day, its colorful and sweet and made with the Lucky Charms cereal.

Course Dessert
Cuisine American
Keyword Cake Decorating, Lucky Charms Cereal
Prep Time 30 minutes
Cook Time 30 minutes
Cooling Time 30 minutes
Total Time 1 hour
Servings 3 6" cake layers
Author Katie


Cereal Milk Cake

  • 1 cup whole milk
  • 2 cups Lucky Charms cereal (separated from marshmallows)
  • 2 1/4 cups all-purpose flour
  • 2 Tablespoons cornstarch
  • 2 cups granulated sugar
  • 1/2 teaspoon salt
  • 2 teaspoons baking powder
  • 2 sticks or 1 cup unsalted butter, room temperature, cut into cubes
  • 2 whole eggs
  • 2 egg whites
  • 1 teaspoon vanilla extract
  • 2 cups Lucky Charms marshmallows

Vanilla Buttercream

  • 4 sticks or 2 cups unsalted butter, room temperature
  • 1 Tablespoon vanilla extract
  • 1 teaspoon salt
  • 7 ½ cups powdered sugar, sifted
  • 2 Tablespoons heavy cream
  • Food coloring, optional

White Chocolate Milk Spill

  • 12 oz white candy coating chocolate
  • 2 teaspoons coconut oil or vegetable shortening
  • 1-3 balloons


Cereal Milk Cake

  1. This cereal milk cake starts with 1 box of Lucky Charms cereal. This is a little time consuming, but it’ll make a huge difference. Begin to separate the cereal from the marshmallow but don't worry we’ll be using both in this cake. In a small bowl, add 2 cups of cereal with 1 ⅓ cup of warmed milk let this soak for 30-60 minutes. 

  2. In a stand mixer bowl combine all the dry ingredients and whisk them together to de-clump any flour. Place on the mixer with a paddle attachment and start the mixer on low speed. 

  3. Then add the room temperature butter cubes piece by piece into the dry ingredients. Allow the butter to incorporate into the dry mix. The mixture will look like sand when its ready for the next step. This could take a few minutes.    

  4. Next, add the vanilla extract and eggs one at a time and along to incorporate. The batter will begin to smooth out. Now add the strained cereal milk to the batter. Once all the milk is added then increase the mixer speed to medium to smooth out the cake batter. Keep mixing for one minute until it’s thick and creamy. Stop the mixer and scrape down the sides of the bowl to make sure everything is incorporated.  

  5. A single batch of this cake recipe makes enough for 3 – 6” cake layers or 2 – 8” cake layers. To prepare the cake pans, spray each pan with cooking or baking spray and then line the bottom of the pan with parchment paper. Place the parchment paper on top of the cooking spray to prevent the cake from sticking to the bottom of the pan.

  6. To make 3 cake layers evenly pour or scoop the cake batter into the 3 pans or weight out by using a baking scale. Place the cake pans into the preheated oven and bake for 30-35 minutes. Depending on how high or the size of the pan the baking time may vary. 

  7. After 30 minutes, carefully check the cakes with a toothpick. If the toothpick comes out clean, then the cakes are done, if not add additional time and recheck them. 

  8. Once the cakes are done baking, remove the cakes from the oven and set aside to cool. Allow to cool for 10 minutes, the cake pans should be cool enough to touch but still warm. Then carefully remove the cakes from the pan by turning the cakes upside and flip them back upright. Leave the parchment paper on the bottom to finish cooling. If the cakes are sticking to the cake pans, carefully run an off-set spatula or a small knife around the edges of the cake then flip the cakes out of the pan. That should release the cake from the sides of the pan.

  9. After the cakes have cooled completely, wrap in plastic wrap and freeze for 30 minutes. At this stage, you can cover the cakes and leave them in the freezer for several days or up to a month before decorating them. I prefer to chill the cakes before decorating so they are easier to handle and decorate later.  

Vanilla Buttercream

  1. In a stand mixer bowl, add the unsalted room temperature butter. Mix on medium-high until the butter is light in color and fluffy. Stop the mixer every few minutes to scrape down the sides of the bowl to make sure all the butter is well blended. This step can take up to 5 minutes and is essential to whipping air into the butter, so your buttercream is the creamy smooth texture we want. 

  2. Once the butter is light in color and fluffy, continue to mix on medium and add the vanilla extract and salt. Scrape down the sides of the bowl again before moving to the next step. 

  3. Then gradually add half of the sifted powdered sugar to the butter mixture. Next, add 1 ½ Tablespoons of the heavy cream. Scrape down the sides of the bowl and especially the center of the bowl to make sure all the powdered sugar is getting incorporated. 

  4. Finally, add the last half of the powdered sugar and mix on medium-high. Continue to mix and scrape down the sides of the bowl until you don't see any more powdered sugar. If the buttercream is a little stiff, then mix an additional ½ tablespoon of heavy cream. Continue to mix until you have a creamy and smooth buttercream. 

  5. The vanilla buttercream is ready to use. Fill a pastry (piping) bag with the buttercream for frosting cupcakes or a cake.

White Chocolate Milk Spill

  1. In a small microwavable bowl combine the white candy coating chocolate and the coconut oil. Melt the white chocolate and coconut oil together in the microwave. Heat 30 seconds at a time about 1 ½ minute until the chocolate is melted. Then pour the chocolate into a piping bag or Ziploc bag and set aside.

  2. Then blow up a balloon about 4 inches wide and place knot side down onto a drinking cup or measuring cup to hold the balloon in place.

  3. Next, carefully pour the white chocolate over the balloon starting in the center that’ll slowly drip down the sides. Gently tap the balloon, so the chocolate evens out and slides down the balloon. Then place the balloon and cup in the refrigerator to cool and harden for 30 minutes before popping the balloon. (Note: you might want to make more than one balloon as sometimes it’s difficult to remove the balloon without cracking the white chocolate). 

  4. Make sure the chocolate is really cold and is dried so you can easily pop the balloon and remove it, so you get the whole milk spill for the top of the cake. 

Decorating This Cake

  1. Remove the chilled cakes from the freezer and carefully slice the top of any dome of the cakes off to make them level and flat. This makes the stacking process much more manageable. 

  2. Next is decorating, use an offset spatula for layering the vanilla buttercream and Lucky Charms cereal and marshmallows in between each cake layer. Continue to a crumb coat, so the whole cake is covered then chill in the fridge for 20 minutes until the crumb coat has set. For tips and tricks with stacking, filling and frosting your cake see this tutorial, it’s perfect for beginners! 

  3. After the crumb coat is chilled add a thicker layer of buttercream onto the cake for the final coat. This is where you make the edges straight and pretty. Then place the Lucky Charms Marshmallows around the bottom edge of the cake going up four rows.    

  4. To finish the cake, add the white chocolate milk spill to the top of the cake and sprinkle Lucky Charms cereal and marshmallows on the top edge. And that completes this magically delicious St. Patrick’s Day Cake!

Recipe Notes

Double Cake Recipe for 3-8” or 3-9” cake layers. 

For later use store buttercream in airtight containers and store in the refrigerator for up to 2 weeks. When you’re ready to use the vanilla buttercream, place it on the counter to come back up to room temperature. Then mix it on medium-high to make it smooth and creamy once again.