There are some desserts that don’t just show up to the party—they are the party. And a tall, sprinkle-packed Funfetti Birthday Cake is definitely one of them. The second you slice in and see those rainbow jimmies scattered through soft white cake, it’s like your kitchen instantly gets a little louder (in the best way).
This version is the kind of homemade funfetti cake that makes boxed mix feel… fine, but forgettable. You get three plush layers with a tender crumb (thanks to egg whites and buttermilk), plus that dreamy balance of butter + oil that keeps everything moist. Then it’s all wrapped up in a fluffy vanilla buttercream and finished with extra sprinkles because—obviously.
Why You’ll Love This Funfetti Cake
- Soft, moist white cake layers with a light, fluffy texture
- Rainbow sprinkles baked right in for that classic confetti look
- Sweet, creamy vanilla buttercream that’s easy to spread and pipe
- Perfect for birthdays, celebrations, and “just because” days
Key Ingredients That Make It Work
Here’s what gives this cake its signature texture and flavor:
All-Purpose Flour
You can make a seriously tender cake with regular all-purpose flour—no fancy flour required.
Butter + Oil
Using both gives you the best of both worlds: buttery flavor and extra moisture.
Buttermilk
Buttermilk keeps the crumb soft and tender while adding moisture.
Egg Whites
Egg whites help create that classic “white cake” look and a fluffier texture.
Sprinkles
For funfetti cake, rainbow jimmies are the go-to. They hold up best in the batter and give you the prettiest pops of color (plus you’ll want more for decorating).
Vanilla Buttercream
A simple, classic vanilla frosting made with butter, powdered sugar, vanilla, a pinch of salt, and heavy cream to get the texture just right.
Equipment You’ll Need
- 3 (8-inch) cake pans
- Parchment paper
- Cake strips (optional, but helpful for even layers)
- Stand mixer with paddle attachment or handheld electric mixer
Ingredients
For the Cake
- 3¾ cups all-purpose flour (450g)
- 2½ teaspoons baking powder
- 1 teaspoon salt
- 2⅓ cups granulated sugar (466g)
- 1 cup unsalted butter, softened (227g)
- ⅓ cup vegetable oil (80mL)
- 1 tablespoon vanilla extract
- 1⅓ cups buttermilk, room temperature (320ml)
- 7 large egg whites, room temperature
- ⅔ cup rainbow jimmies (100g)
For the Frosting
- 1 pound unsalted butter (450g)
- 2 pounds powdered sugar (900g)
- ½ teaspoon salt
- 1 tablespoon vanilla extract
- 3 to 4 tablespoons heavy cream
- Rainbow sprinkles, for decorating
How to Make Funfetti Birthday Cake
1) Prep the pans and oven
Preheat the oven to 350°F. Lightly grease three 8-inch round pans (baking spray or butter + flour), then line the bottoms with parchment paper. If you use cake strips, wrap them around the pans for flatter, more even layers.
2) Mix the dry ingredients
In a large bowl, sift together the flour, baking powder, and salt. Set aside.
3) Cream butter, sugar, and oil
In a stand mixer (or using a hand mixer), beat the sugar, softened butter, and oil on medium speed until smooth and creamy—about 3 minutes.
4) Add egg whites + vanilla
Add the egg whites in three additions, mixing on low until each is combined before adding the next. Scrape down the bowl as needed. Add the vanilla and beat briefly until fluffy (about 20 seconds).
5) Alternate dry ingredients and buttermilk
Add one-third of the flour mixture and mix on low until combined. Add half of the buttermilk and mix again. Repeat with another third of the flour, the remaining buttermilk, and finish with the last third of the flour—mixing between each addition. Scrape down the bowl and make sure the batter is smooth.
Gently fold in the rainbow jimmies with a silicone spatula.
6) Bake the layers
Divide the batter evenly among the pans and smooth the tops. Tap each pan a few times on a towel-lined counter to help release big air bubbles.
Bake for 32 to 38 minutes, rotating the pans after 20 minutes, until the centers spring back when lightly pressed.
Cool the cakes in the pans for 10 minutes, then turn out onto wire racks and remove the parchment. Cool completely before frosting.
Vanilla Buttercream Frosting
In a large bowl, beat the butter and salt on medium speed until very soft and smooth (about 2 minutes).
With the mixer on low, gradually add the powdered sugar. Add heavy cream 1 tablespoon at a time as needed to keep the frosting creamy. Beat in the vanilla, then increase speed to medium and beat 1–2 minutes until fluffy and smooth.
Assemble and Decorate
- Place one cooled cake layer top-side up on a cake stand. Spread 1 cup frosting evenly to the edge.
- Repeat with the second and third layers.
- Scoop 1 cup frosting into a piping bag fitted with a large open star tip (Ateco 869 style).
- Frost the top and sides of the cake with the remaining buttercream.
- Press rainbow sprinkles around the bottom of the cake, about 2–3 inches up, like a sprinkle “skirt.”
- Pipe 8–10 frosting dollops around the top edge and finish with more sprinkles if you’d like.
Helpful Notes and Easy Swaps
No buttermilk?
Stir together 1⅓ cups (320ml) whole milk with 1 tablespoon lemon juice or vinegar. Let it sit briefly, then use as directed.
Want a different frosting?
You can swap in any frosting you love—this cake base pairs well with lots of options.
Funfetti Birthday Cake Recipe
Instructions
For the Cake
- Preheat oven to 350°F. Grease and line three 8-inch pans with parchment.
- Sift flour, baking powder, and salt; set aside.
- Beat sugar, butter, and oil until creamy (3 minutes).
- Add egg whites in 3 parts, mixing between additions. Add vanilla and beat briefly.
- Alternate adding dry ingredients and buttermilk, ending with dry. Fold in sprinkles.
- Divide batter into pans, tap to release bubbles, and bake 32–38 minutes (rotate at 20).
- Cool 10 minutes in pans, then transfer to racks to cool completely.
For the Frosting
- Beat butter and salt until smooth (2 minutes).
- Add powdered sugar gradually; add heavy cream as needed to keep it creamy.
- Mix in vanilla, then beat 1–2 minutes until fluffy.
Assembly
- Frost between layers (about 1 cup per layer).
- Frost the outside. Pipe dollops around the top edge.
- Press sprinkles around the bottom and garnish with more sprinkles.
If you want this to scream “birthday,” don’t be shy with the sprinkles. Funfetti Birthday Cake is supposed to be joyful—and this one absolutely delivers. 🎉🎂