This simple Funfetti Oreo Cake has soft, tender funfetti cake layers loaded with sprinkles and is covered in creamy Oreo American buttercream! This funfetti layer cake is perfect for birthdays because, come on, what's better for a birthday party than sprinkles? I've decorated this cake with even more rainbow sprinkles and mini Oreos! The funfetti cake is super soft and moist thanks to buttermilk and swapping out some of the butter for oil.

A slice of Oreo funfetti cake on a small plate.

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Ok, so once I made my funfetti cake with strawberry frosting, I wanted to make ALL the funfetti recipes. (Am I planning on making a funfetti sheet cake this week? Yes, yes, I am.)

This Oreo funfetti cake uses the same cake base as the strawberry funfetti cake, so you're getting my tried-and-true vanilla cake packed with rainbow sprinkles.

I then covered the cake in my fave Oreo frosting, which is an American buttercream. American buttercream is one of the easiest types of frostings to make since it's just butter mixed with confectioners' sugar. I added finely crushed Oreo crumbs to give it that Oreo flavor!

If you're looking for more indulgent layer cakes, you need to try my triple chocolate layer cake, Oreo red velvet cake that uses the same delish Oreo buttercream, or chocolate covered strawberry cake.

Why you'll love this recipe!

Simple Recipe: I've made this layer cake as simple as possible. You will need a mixer for both the cake and the frosting, so keep that in mind when prepping for this recipe!
Oreo 🤝 Funfetti: You're getting the best Oreo flavor thanks to the Oreo cookie crumbs in the frosting, then a combo of vanilla extract and rainbow sprinkles in the plushy funfetti cake gives us those nostalgic birthday cake flavors!

Grab your ingredients!

All the ingredients needed to make a funfetti Oreo cake, weighed out into small bowls.

Oreo Crumbs: you can buy ready-made Oreo cookie crumbs at some grocery stores, but I just pulsed them in a food processor or blender. You can also place them in a ziploc bag and crush them with a rolling pin! Make sure you get fine crumbs or it'll be hard to pipe the frosting out with a piping bag.
Rainbow Sprinkles: I recommend using long-stranded sprinkles, also known as jimmies, and not the little round nonpareils that will just bleed in the batter.
Oil: I swapped out some of the butter for neutral oil (like sunflower oil, vegetable oil, or canola oil). Neutral oil in cake is going to keep it soft and plush for days, but since we still have a bit of butter we still get that buttery taste.
Buttermilk: I love using buttermilk in cake recipes because it not only gives them a slightly tangy taste but also makes the cake extra moist.

Let's make this cake!

Creamed butter, oil, and sugar in a mixing bowl.

Step 1: Preheat the oven to 350ºF and grease and line two 8-inch cake pans. In a stand mixer, combine the granulated sugar, oil, and butter until light and fluffy.

Step 2: Add the eggs one at a time, scraping after each addition. Mix in the vanilla extract. Mix the flour with the salt and baking powder in a small bowl.

Funfetti cake batter in a large mixing bowl.

Step 3: Add ⅓ of the dry ingredients, then mix. Add in half of the buttermilk and mix again. Repeat this once more, ending with the dry ingredients. Stir in the sprinkles.

Funfetti cake batter in two cake pans, unbaked.

Step 4: Pour the funfetti cake batter into the prepared pans. Bake for 30-35 minutes, or until a toothpick inserted comes out clean. Let cool for 10 minutes in the pan, then let cool on a wire rack.

Vanilla frosting in a large mixing bowl.

Step 5: In a stand mixer or with a handheld mixer, beat the butter with the confectioners' sugar on low speed until combined. Beat on medium-high speed until thick.

Step 6: Add the vanilla extract and salt and mix. Then pour in the Oreo cookie crumbs and mix on medium speed. Slowly pour in the heavy cream until the frosting is the consistency you want.

Decorating the Cake

Use a bread knife, a large serrated knife, or a cake leveler to even out the tops of the cake so they're flat and even.
Assemble the cake using an offset spatula, spreading frosting in between the layers and on the outside of the cake.
To get that swirl on top, place the cake on a cake turntable. Place the tip of a small offset spatula on the edge of the cake, and slowly turn the turntable. Continue doing this until you get to the middle of the cake.
I used a Wilton 1M piping tip to pipe swirls on the edge of the cake, and then placed a mini Oreo cookie on top of every other swirl.

An overhead shot of an Oreo frosted cake with rainbow sprinkles.

Expert Baking Tips!

Make sure the Oreo cookie crumbs are really finely chopped up, otherwise they'll get stuck in the piping tip when you're decorating the cake.
Make sure the ingredients like the eggs, butter, and buttermilk are at room temperature before you start baking. I recommend taking them out of the fridge an hour or two before baking. Otherwise, the cake batter might not mix properly.
To get rid of any air bubbles in the frosting, use a large rubber spatula to mix the frosting by hand for a couple of minutes before frosting the cake. This is an arm workout, and I am sorry for that!

Storage & Make Ahead

Once frosted, I recommend storing this cake in an airtight container in the fridge. Don't have a container big enough? Then once you've sliced the cake, press a piece of parchment paper on the exposed slice of cake so it doesn't dry out.

Let the cake come to room temperature before serving!

You can make the cake layers up to 3 days ahead. Once cooled, tightly wrap in plastic wrap and store at cool room temperature until ready to frost.

A slice of Oreo funfetti cake being lifted out with a cake server.

Make these Oreo recipes next!

Ella from Alpine Ella is holding a cake stand with cupcakes on it.

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Thank you!

Ella