Name: Mini Confetti Layer Cake
Prep time: 45 min
Cook time: 25 min
Total time: 2 h 25 min
Yield: 8
Cuisine: American
Ingredients: 4 egg yolks (use the ones leftover from the cake!); 1/2 cup granulated sugar (100g); 3 Tablespoons water (45 ml); 1 cup salted butter (226g) at room temperature; 1 Tablespoon vanilla extract (15 ml); 1/2 cup powdered sugar (50g); 2 Tablespoons heavy cream (30 ml); ½-1½ cups rainbow sprinkles; 4 egg whites, from fresh eggs (not pasteurized!); 1 cup granulated sugar, divided (200g); 8 Tablespoons unsalted butter (113g), at room temperature; 1 ⅔ cups all purpose flour (220g); 1 ½ teaspoons baking powder (6g); ¼ teaspoon salt (1g); 1 Tablespoon canola oil (15 ml); 1 teaspoon vanilla extract or vanilla bean paste (5 ml); ⅔ cup whole milk (160 ml); ⅓ cup rainbow sprinkles (65g)

Jump to Recipe

Introducing the perfect birthday cake for a small and intimate celebration: This fluffy white cake is filled with sprinkles and topped with a custardy cake batter French buttercream. This mini confetti layer cake is great for any occasion worth celebrating: birthdays, anniversaries, retirements, Fridays…

This small 6″ layered birthday cake serves 8-10 people.

A fork takes a piece out of a slice of mini confetti layer cake. — It’s hard not to smile when you’re adding so many sprinkles to one thing.

Ingredients for Mini Confetti Layer Cake

This white cake recipe has a few extra steps for ultimate fluffy cake goodness—but no unnecessary ingredients! With just a few upgrades (egg whites turned into meringue, American buttercream into French buttercream), this confetti cake goes from “yum” to “I can’t wait for the next birthday party!”

Ingredients for the Mini Confetti Layer Cakes

Egg whites, from fresh eggs. Egg whites are whipped into a meringue. That’s what will give this cake its light and fluffy airiness, along with some structure.
Granulated sugar. Granulated sugar will strengthen the meringue and prevent it from deflating too quickly and will also keep the entire cake moist.
Unsalted butter. Use unsalted butter to keep your cake moist and not overly salty, as each butter brand uses a different amount of salt in each stick.
All purpose flour. This recipe works well with all-purpose flour, not cake flour, to give the cake its structure.
Baking powder. This white cake is light and fluffy due to the lift baking powder gives, along with the air from the meringue.
Salt. Just a pinch helps to enhance all the flavors.
Canola oil. There are no egg yolks in this recipe, so we need to add a little extra fat to make up for it. You may use any neutral oil you like in place of canola oil.
Vanilla extract or vanilla bean paste. This cake is delicious even without vanilla extract, but I recommend adding it for an extra boost of flavor.
Whole milk. The fat in whole milk works best with this cake, since it does not have the fat from the egg yolks. You may substitute 2% or 1% milk if needed, but I recommend using whole milk for the best texture.
Rainbow sprinkles! The long, jimmies sprinkles like this are the best kind to use here.

Ingredients for the Birthday Cake Batter French Buttercream

Egg yolks. Egg yolks give this buttercream a custardy richness like none other. Use the egg yolks reserved from the cake for a no-waste cake recipe!
Granulated sugar. This is a great buttercream to make when you don’t have a lot of powdered sugar on hand.
Water. Add a touch to the sugar to help the syrup heat evenly.
Salted butter. This is what gives the buttercream its birthday cake batter flavor without any emulsifiers! Do not substitute unsalted butter.
Vanilla extract. Necessary for a good vanilla buttercream.
Powdered sugar. This helps to offset the saltiness of the buttercream and adds stability and flavor.
Heavy cream. This helps reduce the saltiness of the buttercream and improve the texture.

Ingredients needed to make the white sprinkle cakes. — This recipe requires four eggs—the whites are used in the cake, and the yolks are used in the buttercream.

Ingredients needed to make birthday cake batter French buttercream on a counter. — This recipe requires four eggs—the whites are used in the cake, and the yolks are used in the buttercream.

Quick Tips for Prepping Mini Confetti Layer Cake

I combined two cake-making methods into one recipe for the lightest and fluffiest white cake I’ve ever tasted. First, whip the egg whites into a meringue. Then, reverse cream the dry ingredients and beat in the liquid ingredients. Finish by folding in the meringue. This method requires an extra bowl to hold the meringue, but the difference it makes is more than worth an extra minute at the sink.

Mixing Up the Confetti Cake Batter

Key things to note: Whip the egg whites with about half of the sugar. This will stabilize the meringue and prevent it from deflating as you reverse cream the other ingredients. I recommend using a stand mixer or hand mixer, as whipping egg whites to soft peaks can take a while without one.

Transfer the meringue to another bowl, then thoroughly whip out your mixing bowl to reverse cream the dry ingredients.

A whisk attachment is held up with a clump of soft-peaked meringue to add to the batter for mini confetti layer cakes. — Meringue is an easy way to incorporate more air into cake batter without risking too much gluten development.

Use a silicone spatula to scrape out the meringue from the bowl. — Meringue is an easy way to incorporate more air into cake batter without risking too much gluten development.

Reverse creaming combines all the dry ingredients in the cake with the fat before adding in any liquid. This coats the flour in fat, which is unable to properly hydrate. (That’s a good thing!) The flour can’t create nearly as much gluten, so instead of a tough and chewy crumb, you end up with a moist, tender crumb that melts in your mouth.

Pour the milk, canola oil, and vanilla into the mixer while on low, then beat for a minute until the batter is smooth. Scrape down the sides and bottom of the bowl to ensure there aren’t any sneaky lumps hiding out.

A mixing bowl is filled with the dry ingredients of mini confetti layer cakes and creamed together with butter.

Milk is streamed into a mixing bowl with what appears to be breadcrumbs inside.

Then, add your sprinkles!

Finally, fold in the meringue. It won’t feel like it’s mixing at the start, but keep at it.

Use large strokes that hug the sides of the bowl to reduce deflating the meringue. Continue folding in the meringue until no streaks remain.

This process usually takes me no longer than two minutes.

A measuring cup pours sprinkles into a thick mini confetti layer cake batter.

A mixing bowl with mini confetti layer cake batter above a bowl full of meringue.

Baking the Cakes

The easiest way to divide your cake into cake pans is to weigh how much batter you have in each pan. This is the best way to ensure even cake layers that all finish baking at the same time.

These cakes are small, so they don’t take long to bake. I use light-colored aluminum 6″ cake pans that heat incredibly evenly. If you’re using dark-colored pans, which absorb more heat, check on your cakes five minutes early.

Three cake pans are filled with sprinkle cake batter. One rests on a digital scale. — To ensure the cakes are done at approximately the same time, put about the same amount of batter in each pan. I use a scale to weigh mine.

Three baked cake rounds cool on a wire rack covered with parchment paper. — To ensure the cakes are done at approximately the same time, put about the same amount of batter in each pan. I use a scale to weigh mine.

Quick Tips for Prepping Birthday Cake Batter French Buttercream

French buttercream is more difficult to make than American buttercream, but there’s no reason why you shouldn’t be able to make it at home.

The number one problem people have with French buttercream is mixing the hot sugar syrup into the egg yolks quickly enough while the beater is beating fast enough without splattering it everywhere.

It’s easier than it sounds, I promise.

Making the Custard

The egg yolks should be at room temperature. If they’re cold, the sugar syrup will cool immediately upon contact.

Use level 2 or 4 on your KitchenAid or stand mixer—not just the “stir” option. Level 4 combines the syrup with the egg yolks quickly enough to prevent them from curdling but doesn’t splatter.

As you pour the syrup into the bowl, make sure it is running down the side of the bowl before it meets the yolks. That will prevent splatters and helps make sure all the syrup makes its way into the mixture. A small saucepan with a spout really helps this process along.

Keep pouring the syrup onto that same line of syrup in one slow and steady stream. Go slow enough so that there isn’t a puddle of syrup waiting to be incorporated. That puddle is hot, and it will begin to curdle the yolks if it’s not spread out evenly.

If your yolks end up curdling, don’t worry about it overmuch! You can always push the final product through a fine mesh strainer to get rid of any large lumps. No one will be the wiser!

A candy thermometer rests on the side of a small saucepan with bubbling syrup. — Note the single, thin stream of syrup going directly into the egg yolks at the bottom of the bowl.

A small saucepan pours syrup into a mixing bowl with egg yolks. — Note the single, thin stream of syrup going directly into the egg yolks at the bottom of the bowl.

Adding in the Salted Butter

A friendly reminder: Use salted butter. Unsalted butter just won’t have the same flavor.

When you’re ready to add the salted butter to the French buttercream, the bowl should be almost cool to the touch. The butter will melt if you add in the butter when the custard is warm. Then, the buttercream won’t whip up properly.

Ensure the butter is at room temperature. If your butter is too cold, it will not whip properly. If your butter is too warm, it won’t aerate easily and can turn out a bit dense.

The buttercream comes together more easily when the butter is introduced in pieces and not all at once. Once incorporated, the French buttercream will be dense until the next step.

A pale yellow liquid at the bottom of a mixer bowl. — The custard will have cooled significantly by the time it reaches the ribbon stage, where you can see the trails the custard leaves.

A hand holds a small piece of butter in front of a mixer with a whisk attachment. — The custard will have cooled significantly by the time it reaches the ribbon stage, where you can see the trails the custard leaves.

Making the Buttercream Taste like Cake Batter

Finally, add in your vanilla, powdered sugar, and heavy cream. Beat them all together for no less than three minutes, and enjoy your wonderfully fluffy, one-of-a-kind, birthday cake batter French buttercream.

A hand pours heavy cream into French buttercream in a mixer. — I generally switch to a beater attachment to knock out any large air bubbles at the end, but I opted against it this time.

A small spatula holds up a load of silky French buttercream. — I generally switch to a beater attachment to knock out any large air bubbles at the end, but I opted against it this time.

Can I Make this Buttercream with Unsalted Butter?

You can, but it’s not going to taste the same. I have attempted making this buttercream with unsalted butter, then compensating by adding salt during during the whipping stage. The buttercream turned out a bit grainy, and it contained unpleasant pockets of saltiness. This recipe needs salted butter for the flavor to turn out right.

Do I Need to Use a Candy Thermometer?

No, you don’t, but you will need a thermometer of some kind! A candy thermometer is certainly helpful (I love this inexpensive digital one from CDN) but not required. Any instant-read thermometer will do.

Quick Tips for Assembling Mini Confetti Layer Cake

Do not frost a partially-cooled cake. If running low on time, wrap a slightly warm cake in plastic wrap and put it in the fridge until it is fully chilled. Frosting and filling a warm cake will only result in goopy buttercream, a lack of structural integrity, and probably a few frustrated tears (speaking from experience!).

To layer your cake, place a dollop of birthday cake batter French buttercream on a cake turner and firmly press a cake round onto it. Apply another dollop of buttercream and press a white cake layer onto it. Pipe a ring of buttercream around the layer, then spread it evenly across the top of the cake layer. Use about ½ cup.

Then top with another cake layer, pressing lightly but firmly to seal it. Repeat.

Once your third layer is in place, spread a light coating of buttercream around the top and edges of the cake to seal in any crumbs. Refrigerate for at least 15 minutes, then frost with the remaining buttercream. Smooth with a bench scraper for perfect edges.

A woman spreads French buttercream over a mini confetti layer cake on a turntable.

A woman smooths buttercream over the sides of a mini confetti layer cake.

Dish Cleanup: Dish Mountain

I rate my recipe cleanups on a scale of 1 to 5. 1 is only a handful of dishes, and 5 is everything including the kitchen sink.

My mini confetti layer cake recipe has a cleanup rating of a 5. To cut down on the dishes you have to use and wash at one time, I’d recommend lining your cooling racks with parchment paper and splitting up the bake into two days. I did the dishes for the cake one day and everything else the next.

A collection of dishes used to make mini confetti layer cakes. — The dishes for this mini confetti layer cake aren’t mini, but birthdays only come around once a year!

A collection of dishes used to make birthday cake batter French buttercream. — The dishes for this mini confetti layer cake aren’t mini, but birthdays only come around once a year!

Other Recipes You May Enjoy

Birthdays are special occasions, but you don’t need a special occasion for sprinkles. Here are similar recipes best served with celebrations:

Birthday cake macarons
Confetti cupcakes with French buttercream
Birthday cake batter French buttercream (in case you want the recipe by itself!)