This funfetti sheet cake is soft, fluffy, and topped with a rich vanilla buttercream for the ultimate homemade celebration cake. It’s easy to make, feeds a crowd, and is perfect for birthdays and every happy occasion in between.
Some cakes just make people smile, and this funfetti sheet cake is one of them. It’s soft, fluffy, and packed with colorful sprinkles, all topped with a rich vanilla buttercream that’s perfect for birthdays, celebrations, or anytime you want to bake something fun.
Made completely from scratch, this cake has all the nostalgic charm of the boxed version but with a buttery vanilla flavor and tender crumb that’s even better. Whether you’re baking for a crowd or just looking for an easy celebration cake, this one is sure to disappear fast.
Why You’ll Love This Funfetti Sheet Cake
- Completely from scratch. All the classic funfetti flavor without a cake mix.
- Soft, tender crumb. Butter, oil, cake flour, and buttermilk work together for a cake that’s fluffy yet sturdy enough to slice and serve.
- Perfect for celebrations. Birthdays, graduations, baby showers, office parties, or just because.
- Easy to decorate. A simple swirl of vanilla buttercream, a piped border, and plenty of sprinkles are all it needs.
- Feeds a crowd. A 9″x13″ cake is easy to transport and serves plenty of happy people.
- Great make-ahead dessert. Bake it a day ahead so decorating is even easier.
Key Ingredients
- Cake flour – This gives this cake its soft, tender crumb while still creating slices sturdy enough to frost and serve. If you want that classic bakery-style birthday cake texture, cake flour is the way to go.
- Buttermilk – It adds moisture and a subtle tang that balances the sweetness while helping create a light, fluffy cake.
- Butter and oil – Using both butter and oil gives you the best of both worlds. Butter provides rich flavor, while oil helps keep the cake soft and moist for days.
- Vanilla extract – With a simple vanilla cake like this, good vanilla makes a big difference. It adds warm, classic flavor that pairs perfectly with the colorful sprinkles and buttercream.
- Rainbow jimmies – Stick with jimmies (the long, soft sprinkles) for the best results. They hold their shape well in the batter without bleeding color the way nonpareils often do.
- Vanilla buttercream – A fluffy homemade vanilla buttercream is the perfect finishing touch. It’s rich, creamy, and easy to spread or pipe for a festive look.
How to Make Funfetti Sheet Cake
Mix the batter.
Whisk together the dry ingredients. In a separate bowl, cream the butter and sugar until light and fluffy before mixing in the oil, eggs, and vanilla. Add the dry ingredients in alternating additions with the buttermilk, mixing just until combined after each addition. Take care not to over-mix, which develops the gluten in the flour and can make the cake less tender.
Fold in the sprinkles.
Gently fold the rainbow jimmies into the finished batter with a spatula. Using jimmies instead of nonpareils helps keep the colors bright without bleeding into the batter.
Bake.
Spread the batter evenly in the prepared pan and bake until the top springs back lightly when touched and a toothpick inserted into the center comes out with a few moist crumbs. Let the cake cool completely before frosting so the buttercream stays light and fluffy instead of melting.
Make the buttercream.
Beat the butter until creamy, then gradually mix in the confectioners’ sugar. Add the vanilla, salt, and enough cream to create a smooth, fluffy frosting. Beat for another few minutes to incorporate air for an especially light texture.
Frost and decorate.
Spread the buttercream over the cooled cake, then add a simple piped border if you like. Finish with a generous scattering of rainbow sprinkles for a classic funfetti look.
Tips for Success
- Use softened and room temperature ingredients. Your butter, eggs, and buttermilk will blend together more easily, creating a smooth batter and a tender, evenly textured cake.
- Measure the flour accurately. Too much flour can make the cake dry or dense. For the most consistent results, weigh the flour or spoon it into your measuring cup and level it off. If you want to review measuring techniques, see my tips for how to measure flour.
- Mix just until combined. Once you begin adding the dry ingredients, avoid over-mixing. This helps keep the cake light and fluffy.
- Choose jimmies over nonpareils. Rainbow jimmies hold their shape and color much better during baking. Nonpareils tend to bleed into the batter, resulting in streaks of color.
- Cool the cake completely. Even a slightly warm cake can cause the buttercream to soften and become difficult to spread.
- Decorate to suit the occasion. Keep it simple with extra sprinkles, add a piped border for birthdays, or customize the colors to match holidays, baby showers, graduations, or team celebrations.
Variations and Serving Ideas
- Change up the sprinkles. Swap the rainbow jimmies for seasonal or themed colors to match birthdays, holidays, baby showers, graduations, or team celebrations.
- Add festive decorations. Top the cake with candles, colorful sanding sugar, or a few piped rosettes for an extra-special presentation. You can also finish it with colorful candy pearls or confetti sprinkles.
- Pair it with ice cream. A slice of funfetti sheet cake is even better with a scoop of vanilla ice cream or your favorite birthday cake-inspired flavor.
- Prefer individual servings? Make my confetti cupcakes instead! They have the same festive funfetti flavor in perfectly portable cupcakes that are great for birthdays, parties, and bake sales.
How to Store
Room temperature: You can store the cake in an airtight container at cool room temperature for up to 2 days. If your kitchen is especially warm, it’s best to refrigerate it.
Refrigerator: Cover the cake tightly or store it in an airtight container in the refrigerator for up to 5 days.
Make ahead: You can bake the cake a day in advance. Once it’s completely cool, cover it tightly and store it at room temperature. Frost and decorate the next day before serving.
You can also make the buttercream up to 2 days ahead. Store it in an airtight container in the refrigerator, then let it come to room temperature and re-whip it until light and fluffy before frosting the cake.
Freezer: Freeze the unfrosted cake, well wrapped, for up to 3 months. Thaw overnight in the refrigerator or for a few hours at room temperature before frosting.
You can also freeze individual slices of the frosted cake for an easy make-ahead dessert. Wrap each slice well and freeze for up to 2 months. Thaw overnight in the refrigerator or at room temperature for about an hour.
Bring More Fun to the Dessert Table
Whether you’re celebrating a birthday, marking a special occasion, or simply looking for an excuse to bake something cheerful, this funfetti sheet cake is sure to be a hit. With its soft vanilla crumb, colorful sprinkles, and fluffy buttercream frosting, it’s a homemade classic that’s just as fun to make as it is to share.
If you give this recipe a try, I’d love to hear how it turned out! Leave a comment below and a star rating to let me know what you think, and don’t forget to share a photo of your finished cake on social media and tag Bake or Break so I can see your celebration.
More Celebration Desserts
Funfetti Sheet Cake
Ingredients
For the cake:
- 2 ½ cups (300 g) cake flour
- 2 teaspoons baking powder
- ½ teaspoon baking soda
- ¾ teaspoon salt
- ¾ cup (170 g) unsalted butter, softened
- 1 ½ cups (300 g) granulated sugar
- ¼ cup (60 ml) neutral oil, like vegetable or canola oil
- 4 large eggs, at room temperature
- 2 tablespoons vanilla extract
- 1 cup (240 ml) buttermilk, at room temperature
- ½ cup (80 to 90 g) rainbow jimmie sprinkles, plus more for decorating
For the frosting:
- 1 ½ cups (339 g) unsalted butter, softened
- 5 cups (550 g) confectioners’ sugar, sifted
- 2 teaspoons vanilla extract
- pinch to 1/4 teaspoon salt, to taste
- 2 to 4 tablespoons (30 to 60 ml) heavy cream or milk
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Instructions
To make the cake:
- Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking pan. Line with parchment paper if desired for easy removal after baking.
- Whisk together the flour, baking powder, baking soda, and salt. Set aside.
- In a large bowl, beat the butter and sugar with an electric mixer on medium speed, mixing until light and fluffy.
- Add the oil, and mix until combined.
- Add the eggs one at a time, mixing well after each addition. Mix in the vanilla.
- With the mixer on low speed, add the flour mixture in three portions, alternating with two portions of buttermilk. Mix just until combined.
- Gently fold in the sprinkles.
- Spread the batter evenly in the pan. Bake 32 to 38 minutes, or until the top springs back lightly and a pick inserted into the center comes out with a few moist crumbs.
- Cool completely in the pan on a wire rack.
To make the frosting:
- Using an electric mixer on medium speed, beat the butter in a large bowl until smooth and creamy.
- With the mixer on low speed, gradually add the confectioners’ sugar.
- Add the vanilla, salt, and 2 tablespoons (30ml) of cream (or milk). Add more cream (or milk) a small amount at a time if needed to make a fluffy, spreadable frosting.
- Increase the mixer speed to medium-high, and beat for 2 to 3 minutes until lightened and fluffy.
- Frost the cooled cake. If you like, pipe some of the frosting around the edges. Decorate with more sprinkles.
Notes
- Use rainbow jimmies rather than nonpareils for the best color and texture.
- Measure the cake flour accurately for the softest crumb.
- Mix just until the batter comes together to keep the cake light and tender.
- Allow the cake to cool completely before frosting.
- For neat slices, chill the frosted cake for 20 to 30 minutes before cutting.
- Makes 15 to 24 servings, depending on the size of your slices.
- Store in an airtight container at room temperature up to 2 days.
