Introduction

This Lucky Charms Sheet Cake is a fun and colorful twist on a classic dessert, featuring the cereal’s signature marshmallows baked right into a moist, fluffy cake. It’s topped with a creamy frosting and decorated with sprinkles for an extra pop of whimsy—perfect for celebrations or a playful treat.

A square piece of cake sits on a white plate, featuring two clear layers: the bottom is a thick, soft-looking green cake layer with a slightly rough texture, and above it is a smooth, white creamy layer. Colorful candy pieces in red, blue, pink, yellow, and purple, along with small multicolored sprinkles, are scattered evenly on top of the white layer. In the background, a clear glass baking dish with more of the cake is partially visible, resting on a white marbled surface with a soft white cloth nearby. photo taken with an iphone --ar 4:5 --v 7

Ingredients

3 cups Lucky Charms cereal

2 cups milk

¾ cup cereal milk (reserved from soaking cereal)

1¼ cups all-purpose flour

1¼ teaspoons baking powder

1 tablespoon cornstarch

¼ teaspoon salt

½ cup unsalted butter (room temperature)

2 tablespoons vegetable oil

¾ cup granulated sugar

2 large eggs (room temperature)

2 teaspoons vanilla extract

Green food coloring (optional)

½ cup unsalted butter (softened, for frosting)

3–4 cups confectioners sugar (for frosting)

2 tablespoons cereal milk (for frosting)

1 teaspoon vanilla extract (for frosting)

Rainbow sprinkles (for decorating)

Instructions

Step 1: Preheat the oven to 300ºF. Line a baking sheet with parchment paper or a silicone baking mat.

Step 2: Remove the marshmallows from the Lucky Charms cereal and set them aside for decorating later.

Step 3: Spread the remaining cereal (without marshmallows) on the prepared baking sheet. Bake for 15 minutes, stirring halfway through. Let the toasted cereal cool.

Step 4: In a large bowl, soak the cooled toasted cereal with 2 cups of milk for 15 minutes. Then drain, reserving the milk and discarding the soaked cereal.

Step 5: Preheat the oven to 350ºF. Line a 9 x 13-inch baking pan with parchment paper and lightly coat it with non-stick spray.

Step 6: In a medium bowl, whisk together the flour, baking powder, cornstarch, and salt. Set aside.

Step 7: In a large bowl, beat the ½ cup room temperature butter, vegetable oil, and granulated sugar until light and fluffy, about 2 minutes. Add the eggs, vanilla extract, and ¾ cup of the reserved cereal milk, beating until well combined.

Step 8: On low speed, gradually add the dry ingredients to the wet mixture, mixing until just combined. If desired, add green food coloring and gently mix.

Step 9: Pour the batter into the prepared pan and bake for 28–32 minutes, or until a toothpick inserted near the center comes out mostly clean.

Step 10: Allow the cake to cool completely in the pan before frosting.

Step 11: For the frosting, beat together the softened butter, 3 cups confectioners sugar, 2 tablespoons cereal milk, and 1 teaspoon vanilla extract until smooth, about 2 minutes. Add more confectioners sugar if the frosting is too thin.

Step 12: Spread the frosting evenly over the cooled cake. Decorate with rainbow sprinkles and the reserved Lucky Charms marshmallows.

Tips & Variations

To enhance the cereal flavor, be sure to toast the Lucky Charms (without marshmallows) before soaking, which adds a nice depth to the cake.

If you don’t have green food coloring, you can leave the batter plain or use your favorite color for a festive look.

For a gluten-free version, substitute the all-purpose flour with a gluten-free blend.

Use fresh, room temperature eggs and butter for best mixing and texture results.

Adjust the frosting thickness by adding more milk or confectioners sugar until you reach the desired consistency.

Storage

Store the sheet cake covered tightly at room temperature for up to 2 days or refrigerate for up to 5 days. Allow refrigerated cake to come to room temperature before serving. The frosting is best enjoyed fresh but can be lightly refreshed with a gentle stir if stored overnight. Leftovers can also be frozen for up to 1 month; thaw overnight in the refrigerator before serving.

FAQs

Can I use a different cereal instead of Lucky Charms?

Yes, other colorful or sweet cereals can be used, but the unique marshmallow and oat flavor of Lucky Charms is central to the cake’s charm. Just adjust soaking and baking times as needed.

What is cereal milk and how do I make it?

Cereal milk is the milk left after soaking cereal, which absorbs flavor and sweetness. In this recipe, it’s made by soaking toasted Lucky Charms in milk, then straining out the cereal. It’s used to add a rich, subtle flavor to both the batter and frosting.