A Saint Patrick’s Day cake inspired by the colorful Lucky Charms! Layers of sprinkle cake, fluffy marshmallow cereal buttercream, and Lucky Charms marshmallows.
Lucky Charms Cake
Happy St. Patrick’s Day!
I’d like to say I planned this Lucky Charms cake around St. Patrick’s Day, but really I planned my St. Patrick’s Day around this Lucky Charms cake. The cravings started when a couple friends and I were debating the merits of Lucky Charms replacing the pot-of-gold marshmallows with unicorn marshmallows. I mean. Nothing against unicorns. I love unicorns. But some kind of loyalty to my 90’s childhood makes me a little resentful of the change…
But unicorns or no . . . I had a bowl of Lucky Charms every day for nearly two weeks. (Dear Ericka, my nutritionist whom I love dearly, let’s just pretend those snack entries in myfitnesspal never happened, shall we?) When I started thinking of a St. Patrick’s Day cake… the answer was a little obvious with Lucky (aka Sir Charms for all you trivia buffs), staring off the box at me.
From there . . . Lucky Charms cake. That is, layers of sprinkle cake (a la funfetti) and fluffy marshmallow buttercream swirled with blended cereal and lucky charms marshmallows.
Yes. Yes, please.
Tips & Tricks
Yes! Check my instagram and you’ll find a quick video of me decorating this cake!
Divide your buttercream among three bowls and successively apply slightly more food coloring to each bowl. Load up three piping bags. After your crumb coat, pipe each color over about a third of the cake, from dark to light. At each spot where one color transitions into the next, use the tip of a spatula to swipe from the light into the dark, about an inch. Make little swipes around the the circumference of the cake. This helps the transition look less “perfect” and more natural. Use a cake scraper to scrape the sides of the cake smooth! If the transitions still look too stark, then repeat the little swipes with the spatula and scrape smooth again.
I use quick and easy DIY cake strips. I have a post and step-by-step photos of how to make an easy insulated cake strip. These get me a flat top on all my cake recipes – no trimming necessary!
I used a multi-green and gold St. Patrick’s Day mix from ManvsCakes. To get the look pictured above, I mixed the green and gold sprinkles about 60/30 with a generic rainbow sprinkle mix! (And lucky charms marshmallows, duh.)
If you make this cake, be sure to leave a comment and/or give this recipe a rating! I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! I love looking through the photos of recipes you all have made!
mikaela | wyldflour
6-Inch 3-Layer Cake
A fun St. Patrick's Day cake featuring everyone's favorite cereal!
1 hr, 45 Prep Time
35 minCook Time
2 hr, 20 Total Time
- 2 1/4 cups all-purpose flour
- 3 Tablespoons cornstarch
- 1 1/4 teaspoons baking powder
- 1 1/4 teaspoons salt
- 3/4 cup vegetable shortening (white, if you want white cake)
- 1 1/4 cups granulated white sugar
- 1/4 cup canola or vegetable oil
- 3 egg whites
- 1 Tablespoon clear imitation vanilla
- 1 cup whole milk
- 1/3 cup rainbow jimmies/sprinkles
- 2 cups unsalted butter
- 1 teaspoon pure vanilla extract
- 13 oz marshmallow creme (about 2 1/2 cups)
- 1/4 cup milk
- 1 1/3 cup Lucky Charms cereal (without marshmallows)
- 2 1/2 cups powdered confectioner's sugar
- ~1 cup Lucky Charms marshmallows (without oat cereal)
- St. Patrick's Day-themed sprinkles
- rainbow jimmies
- Prepare the Cake Pans! Butter three six-inch cake pans and line the bottom with a round parchment circle. Prepare insulated cake wraps and wrap each pan to ensure a flat top. Set aside.
- Preheat the oven to 350 degrees Fahrenheit.
- Make the Cake! Measure out the dry ingredients--flour, cornstarch, salt, and baking powder--into a medium bowl and stir together. Set aside. In the bowl of a stand mixer, cream together the shortening and sugar for 2 minutes on medium-high with a paddle attachment. Add oil and beat on medium another minute. Switch mixer to its lowest speed and add vanilla, then each egg white, one at a time, beating for 5-10 seconds on low between each egg, until egg is just incorporated. While continuing to mix on the lowest speed, add 1/3 of the dry ingredients, then half of the milk. As soon as the milk is incorporated, add a second third of the dry ingredients, then the remainder of the milk. As soon as the last of the milk is incorporated, add the remainder of the dry ingredients. Stop the mixer as soon as the dry ingredients are incorporated. Use a spatula to scrape down the sides and fold in the rainbow sprinkles. Divide the batter equally between the three prepared pans and bake for 32-38 mins, until an inserted toothpick does not come out wet. Remove from the oven and let cakes cool for 10 mins in their pans. Then turn out onto a cooling rack to cool completely. (Don't forget to remove the parchment circles.)
- Prepare the Buttercream! Take butter out of the fridge for about 30 minutes to soften. Separate the oat Lucky Charms cereal from the marshmallows until you have 1 1/3 cup of oat cereal. In a small food processor, blitz the oat cereal until as fine as sand. Set aside. In the bowl of a stand mixer, beat the butter with the paddle attachment on high until slightly lighter in color and fluffy, about two minutes. Add vanilla extract and marshmallow creme and beat on high for another minute. Add the blitzed cereal (now about 1/2 cup) and beat until incorporated. Beat in the powdered sugar 1/2 cup at a time. After adding the last of the powdered sugar, beat on high for another minute, then back it down to low for about 10-20 seconds. Stir with a wooden spoon to remove extra air pockets, until the buttercream looks smooth.
- Assemble the Cake! Tape a 6" cardboard cake round to an 8" cardboard cake round and place on a cake turning table. Put a dollop of frosting on the center of the cake round and place the first layer of sprinkle cake down. Spread or pipe a 1/2-inch layer of buttercream over the first layer. Sprinkle 2 tablespoons of lucky charms marshmallows over the buttercream. Press a second sprinkle cake layer over the buttercream. Repeat the buttercream and marshmallow filling and press a third sprinkle cake layer over the buttercream. Crumb coat the entire cake with buttercream and freeze 10-15 mins until buttercream is not sticky to the touch.
- Decorate the Cake! While the cake is chilling, place 1/4 of the buttercream in one small bowl, another 1/4 of the buttercream in a second small bowl, leaving half of the buttercream in your original mixing bowl. Add just enough green food gel coloring to each bowl to create one small bowl of very light green buttercream, one small bowl of medium-green buttercream, and one larger bowl of dark green buttercream. Place each of the three buttercreams in its own piping bag. Pipe dark green frosting around the bottom third of the cake, medium green around the middle third of the cake, and light green around the top of the cake. Scrape down the sides until smooth. Press sprinkles into the bottom third of the cake, using tweezers (or dainty fingers) to carefully place additional sprinkles and lucky charms marshmallows around the cake. Add a 1M tip to the dark green piping bag and pipe swirls on top of the cake. Top with some sprinkles and Lucky Charms marshmallows. Refrigerate and remove 60ish minutes before serving!
Note that the longer the cake sits, the more moisture the lucky charms marshmallows will absorb. They still taste great--but if you want them to still be crisp, then I recommend decorating the day of your event. Also - remember that as a white cake, sprinkle cake tends to lose moisture more quickly. Eat this cake within a couple days or freeze leftover slices (individually wrapped in plastic wrap). You can defrost slices by leaving them on the counter for an hour or so before eating.
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