Get ready for a magically delicious treat! This Lucky Charms Cake features cereal baked into a from-scratch sheet cake and topped with those irresistible marshmallows!

a slice of green sheet cake topped with frosting and Lucky Charms marshmallows.

Lucky Charms Sheet Cake

If you’re looking for an easy cake recipe with a hint of Irish charm, this Lucky Charms sheet cake is perfect! A fun and festive cake recipe garnished with Lucky Charms — this cake is just as delicious as it looks! Talk about the perfect St. Patrick’s Day party treat!

Here’s the breakdown:

First, we started with a from-scratch sheet cake. We infused the flavor of the Lucky Charms cereal into milk that we used to make the cake batter. So the cake actually tastes like Lucky Charms cereal!

Then we topped this tasty sheet cake with a rich vanilla buttercream frosting, which is decked out with a layer of Lucky Charms marshmallows.

The result is a homemade cake that actually tastes as good as it looks!

We’ll show you how to make it from a box cake mix too, if you’d like a shortcut recipe!

Related: Love Lucky Charms? Try our Lucky Charms Marshmallow Squares recipe too!

Cake Ingredients

For your convenience, I’ve included shop-able ad links to some of the products used to make this recipe; disclosure policy available here.

3 cups Lucky Charms, cereal separated from marshmallows
2 cups Milk
1 1/4 cups All-Purpose Flour
1 1/4 teaspoons Baking Powder
1 Tablespoon Cornstarch
1/4 teaspoons Salt
1/2 cup Unsalted Butter, softened
2 Tablespoons Vegetable Oil
3/4 cup White Sugar
2 Eggs, room temperature
2 teaspoons Vanilla Extract
Green Food Coloring, as needed (plant-based dye can be used)

For the Frosting:

1/2 cup Butter, softened
3-4 cups Powdered Icing Sugar
2 Tablespoons Cereal Milk
1 teaspoon Vanilla Extract
Rainbow Sprinkles, as desired

Kitchen Tools Used

9×13″ baking pan or baking dish
Non-slip mixing bowls
Stand mixer or electric hand mixer

a forkful of green sheet cake with Lucky Charms marshmallows on top.

Instructions

These are the directions to make the cake itself from scratch. You can also make it using a box cake mix, for a time-saving tip! More details on that in the “Frequently Asked Questions” section.

To Prep:

Separate the Lucky Charms cereal pieces from the mini marshmallows.
Preheat oven to 300 degrees and spread the Lucky Charms cereal (without marshmallows) on a lined baking sheet. Bake for 15 minutes and give cereal a stir at the halfway point. Remove from oven and allow to cool.
Increase oven temperature to 350°F and coat a 9 x 13″ baking dish with cooking spray.

3 photo collage showing soaking cereal in milk and straining.

To Make the Cake:

Soak the cooled cereal pieces in a large bowl of milk for 15 minutes. Pour the bowl’s contents through a strainer and keep the milk. You can toss the cereal.
In a large mixing bowl (you can reuse the one you soaked the cereal in previously), cream together the butter, oil, and sugar for about 2 minutes. The mixture should be light-colored. (You can also use the bowl of a standing mixer if preferred, with the paddle attachment).
Mix in the eggs, vanilla extract, and 3/4 cup of the cereal milk.
In a separate mixing bowl, whisk together the flour, baking powder, cornstarch, and salt. Add the dry ingredients to the bowl of wet ingredients and mix until just combined.
Add a few drops of green food coloring and mix until you have your desired shade of green. Keep in mind that the cake will lighten up slightly after baking.
Pour batter into your prepared casserole dish and bake for 28-32 minutes, until a toothpick inserted in the center of the cake comes out clean.
Remove from oven and allow to cool completely before frosting.

4 step photo collage showing how to make cake with Lucky Charms cereal

To Decorate the Cake:

In a large mixing bowl, beat together the butter, powdered sugar, 2 Tablespoons of the cereal milk, and vanilla extract, until stiff peaks form.
Use an offset spatula to spread a generous layer of buttercream frosting on top of the cooled cake. Top the frosting layer with Lucky Charms marshmallows and festive sprinkles.

serving a piece of Lucky Charms sheet cake.

Video Demo:

Frequently Asked Questions

Can You Use a Box Cake Mix?

Sure! We included directions for a from-scratch cake, because if you have time, everything tastes better from scratch!

However, as a time-saver, you can use a box of white cake mix instead. You will want to toast the cereal pieces and soak in milk, as directed in the original recipe.

Then, use this cereal-infused milk in place of the liquid called for in the box cake directions. Even if the box cake mix calls for water, you can use this milk to add more flavor. Use the same amount as listed on the box (versus the 2 cups in our recipe).

Stir in green food coloring and bake according to the package directions. Remove from oven, frost, and decorate!

Does This Cake Need to be Refrigerated?

No, this cake does not need to be refrigerated, as it uses buttercream frosting. Keep any leftover cake at room temperature in an airtight container, or in the cake pan covered with plastic wrap or foil.

The cake should stay fresh for 5 days, or even up to a week.

More St. Patrick’s Day Recipes

Lucky Charms Cake Recipe (Printable Recipe Card)

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5 from 1 vote

Lucky Charms Cake

This Lucky Charms Cake features cereal baked into a from-scratch sheet cake and topped with those irresistible marshmallows!

Prep Time20

Cook Time35

Total Time55

Course: Dessert

Cuisine: American, Irish, Kids

Keyword: cake, lucky charms, Lucky Charms Cake

Servings:

Calories: 319kcal

Author: Stacey aka the Soccer Mom

Cost: $12

Equipment

9 x 13 casserole dish
Mixing bowl
Electric mixer