Step 1

To make Cereal Cake: Have all your ingredients at room temperature. Preheat the oven to 350°F. With a hand mixer or a stand mixer fitted with the paddle attachment, whip the butter for 1 minute on high speed, then scrape down the sides of the bowl with a spatula. Add the sugar to the butter and beat on high speed for 2 minutes. Scrape down the sides of the bowl again.

Step 2

With the mixer on medium-low speed, add the vanilla; then add the eggs one at a time. Scrape down the sides of the bowl midway through.

Step 3

Combine the flour, ground cereal, baking powder, and sea salt in a separate bowl.

Step 4

With the mixer on low speed, add half the flour mixture. When it's mostly incorporated, add half the milk. Add the remainder of the dry and wet ingredients, scraping down the sides of the bowl between additions. Stop mixing as soon as you have a smooth batter.

Step 5

Pour the batter into the prepared pan and bake until the middle of the cake feels springy when you gently press your finger against it (approximately 30-35 minutes). All ovens are different, so it's important to do the fingerprint test to see if the cake is done.

Step 6

Let the cake cool completely before icing.

Step 7

To make Vanilla Icing: With a hand mixer or a stand mixer fitted with the whisk attachment, whip the butter on high speed for 1 minute. Add the vanilla and whip just to incorporate.

Step 8

In a separate bowl, mix the sugar and salt. With the mixer on low speed (otherwise you'll be covered in confectioners' sugar), add the sugar 1 cup at a time, until completely incorporated. Scrape down the sides of the bowl between additions. Whip on high speed for 3 minutes, until light and fluffy.

Step 9

To make Cereal Icing: With a hand mixer or a stand mixer fitted with the whisk attachment, whip the butter on high speed for 1 minute. Add the vanilla and whip just to incorporate.

Step 10

With the mixer on low speed, gradually add the confectioners' sugar, 1 cup at a time, and mix until completely incorporated, scraping down the sides of the bowl between additions. Add the salt and whip on high speed for 3 minutes more.

Step 11

With a spatula, fold in the ground cereal and mix just until combined.

Step 12

To make Vanilla Glaze: With a hand mixer or a stand mixer fitted with the whisk attachment (you can also mix the glaze by hand using a whisk or a spoon), combine the confectioners' sugar, milk, and vanilla. Mix on low speed until smooth. If the glaze is too thick, add a little more milk to thin it to the desired consistency.

Step 13

If not using within 10 minutes of mixing, cover the bowl with plastic wrap to keep the glaze from drying out. Store at room temperature.

Step 14

To make The Cereal Cake: Preheat the oven to 350°F. Butter a 13 x 18-inch half-sheet pan, then line it with wax paper or parchment and butter the paper. Mix the cereal cake batter according to the recipe directions. Pour into the prepared pan and bake until the middle of the cake feels springy when you gently press your finger against it, about 40 minutes. Set aside to cool.

Step 15

Meanwhile, make the vanilla and cereal icings and the cereal crumbs. Add the food coloring to the vanilla icing drop by drop until you reach the desired shade of pink.

Step 16

Use a 6-inch round cutter to cut three rounds from the cake. Place one cake layer on a turntable, frost with about half the pink icing, and sprinkle about a quarter of the cereal crumbs over the top; repeat with the second layer. Place the top layer and frost the entire cake with the cereal icing.

Step 17

Decorate the top and sides of the cake with the remaining cereal crumbs and the Fruity Pebbles. Make the vanilla glaze and drizzle it over each piece of cake as you serve it. It's better to decorate all at once, but if you're assembling the cake the night before, I would hold off adding the cereal to the top until the day of.