Preheat the oven to 350 degrees and spray the 3 cake pans with pam baking spray
Combine all cake ingredients into a standing mixer or large mixing bowl and beat until combined
Divide the batter between the 3 pans and bake in the oven for 28-32 minutes or until a toothpick comes out clean
Allow to cool completely before moving onto the cake board
Using a cake leveler, remove the dome from the cakes to make even
Using a standing mixer, beat together the butter, powdered sugar,vanilla, and heavy whipping cream until combined, smooth and stiff with peaks
Scoop 1/2 C of frosting into 4 bowls
Mix in a few drops of a color into 1 bowl. Repeat steps for remaining colors
Building the cake directions
Using 1 cake layer on the cake board, scoop 1 C of frosting onto the top of the cake and spread evenly
Sprinkle ¾ C of lucky charm cereal all over the frosting layer
Place the second layer of cake on top of the first layer of cereal frosting. Scoop another 1 C of frosting onto the second layer of cake and spread evenly.
Sprinkle another ¾ C of lucky charms
Place the last layer of cake on top
Scoop ¼ C of each colored frosting into their own bags, set aside
Using a knife, blot dollops of the colored frosting all over the side of the cake
Take a flat spatula and lightly spread the colored frosting to create a rainbow effect
Pick out the marshmallows from the cereal and place the randomly on the sides of the cake
Using the colored frosting, pipe dollops of the frosting on top
Fill the center top of the cake with Lucky Charm cereal
Cut and enjoy!
Notes
This cake is designed to be a 3 layer cake. However you could make 36 cupcakes or one 9x13 plus 12 cupcakes.