Confetti Sheet Cake – A Bright, Happy Cake for Any Celebration
Confetti sheet cake is the kind of dessert that brings instant smiles. It’s soft, buttery, and packed with sprinkles that burst into color with every slice. The best part?
It bakes in one pan, feeds a crowd, and doesn’t require any special decorating skills. Whether it’s a birthday, a school celebration, or just a Tuesday, this cake delivers big flavor with minimal fuss. If you love classic vanilla cake but want a playful twist, this one’s for you.
What Makes This Recipe So Good
- Simple, one-pan baking: No stacking or leveling.
A 9×13 pan keeps things easy and sturdy.
- Soft and moist crumb: A mix of butter, oil, and buttermilk gives the cake a tender texture that stays fresh.
- Bright confetti look: Using the right sprinkles ensures even color and no streaking.
- Crowd-pleasing vanilla flavor: Pure vanilla and a touch of almond extract make it taste like a bakery cake.
- Foolproof frosting: Fluffy vanilla buttercream spreads smoothly and holds up well, even when sliced.
Ingredients
For the Cake
- 2 1/2 cups (315g) all-purpose flour
- 1 1/2 cups (300g) granulated sugar
- 2 1/2 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine salt
- 1/2 cup (113g) unsalted butter, melted and cooled slightly
- 1/3 cup (70g) neutral oil (canola or vegetable)
- 3 large eggs, room temperature
- 1 cup (240ml) buttermilk, room temperature
- 1/2 cup (120ml) whole milk, room temperature
- 2 teaspoons pure vanilla extract
- 1/2 teaspoon almond extract (optional but recommended)
- 2/3 cup rainbow “jimmies” sprinkles (plus extra for topping)
For the Vanilla Buttercream
- 1 cup (226g) unsalted butter, softened
- 3 1/2 cups (420g) powdered sugar, sifted
- 1/4 cup (60ml) heavy cream or whole milk
- 2 teaspoons pure vanilla extract
- Pinch of fine salt
Instructions
- Prep the pan and oven: Heat the oven to 350°F (175°C). Grease a 9×13-inch metal baking pan and line the bottom with parchment for easy removal.
- Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, baking soda, and salt until evenly combined.
- Combine wet ingredients: In a separate bowl, whisk melted butter, oil, eggs, buttermilk, milk, vanilla, and almond extract until smooth.
- Make the batter: Pour the wet mixture into the dry ingredients. Whisk gently until just combined with no dry streaks.
Do not overmix.
- Fold in sprinkles: Using a spatula, fold in the rainbow jimmies. Mix lightly to prevent color bleeding.
- Bake: Spread the batter evenly in the prepared pan. Bake 25–32 minutes, or until the top springs back and a toothpick comes out clean or with a few moist crumbs.
- Cool completely: Place the pan on a rack and let the cake cool fully before frosting, about 1 hour.
- Make the frosting: Beat the softened butter on medium-high until creamy and pale, about 2 minutes.
Add powdered sugar in 2–3 additions, mixing on low at first, then increasing speed until fluffy.
- Adjust texture: Add heavy cream, vanilla, and a pinch of salt. Beat 1–2 minutes until smooth, light, and spreadable. Add more cream a teaspoon at a time if needed.
- Frost and decorate: Spread frosting over the cooled cake using an offset spatula.
Add extra sprinkles on top. Slice into squares and serve.
Storage Instructions
- Room temperature: Keep the frosted cake covered at cool room temp for up to 2 days. A cake carrier or tight foil wrap works well.
- Refrigerator: For longer storage, refrigerate up to 5 days.
Let slices sit at room temperature 20–30 minutes before serving for the best texture.
- Freezer: Freeze unfrosted cake tightly wrapped for up to 2 months. Thaw in the fridge overnight. Frost after thawing.
You can also freeze individual frosted slices; freeze solid, then wrap well.
Health Benefits
This cake is a celebration treat, so it leans into comfort over nutrition. That said, there are a few thoughtful choices here. Buttermilk adds tang and tenderness, allowing less fat than an all-butter base alone. A mix of butter and oil gives moisture with a lighter crumb.
You can also control frosting sweetness by adding less powdered sugar or more vanilla and a pinch of salt for balance.
If you want to lighten it slightly, consider using reduced-sugar frosting or serving smaller portions alongside fresh berries. For some, the main health benefit is knowing exactly what’s in your dessert—no preservatives or artificial flavors beyond the sprinkles you choose.
Pitfalls to Watch Out For
- Using the wrong sprinkles: Nonpareils (tiny round balls) bleed color and can tint your batter gray. Use rainbow jimmies for clean, bright specks.
- Overmixing the batter: This can lead to a tough cake.
Mix just until combined and then gently fold in sprinkles.
- Overbaking: Dry cake is usually from a few extra minutes in the oven. Start checking at 25 minutes and look for a springy top.
- Frosting a warm cake: The frosting will melt and slide. Cool completely before topping.
- Too-stiff frosting: If the buttercream tears the cake as you spread, add a teaspoon of cream at a time until it’s soft and fluffy.
Variations You Can Try
- Chocolate confetti: Swap 1/2 cup flour for cocoa powder and use chocolate buttercream.
- Lemon birthday cake: Add 1 tablespoon lemon zest to the batter and 1 teaspoon lemon juice to the frosting.
- Funfetti cream cheese frosting: Use a cream cheese frosting for tangy contrast; fold in a tablespoon of jimmies for a speckled look.
- Gluten-free: Use a 1:1 gluten-free flour blend with xanthan gum.
Let the batter rest 10 minutes before baking for better hydration.
- Almond party cake: Increase almond extract to 1 teaspoon and top with toasted slivered almonds plus sprinkles.
- Rainbow layers, the easy way: Bake in a rimmed sheet, cut in half, stack with frosting in between for a two-layer slab cake.
FAQ
Can I Use a Different Pan Size?
Yes. For a thicker cake, bake in a 10×10-inch pan and add a few minutes to the bake time. For cupcakes, fill liners two-thirds full and bake 16–20 minutes.
Always check for doneness early.
Do I Have to Use Buttermilk?
Buttermilk helps with tenderness and flavor. If you don’t have it, use 1 cup milk plus 1 tablespoon white vinegar or lemon juice. Stir and let sit 5 minutes before adding.
Which Sprinkles Work Best?
Rainbow jimmies (the long, rod-shaped kind) hold their color well in batter.
Avoid nonpareils and sanding sugar, which tend to bleed.
Can I Make the Cake Ahead?
Absolutely. Bake the cake a day in advance, wrap tightly, and keep at room temperature. Frost the day of serving.
You can also make the frosting up to 3 days ahead and refrigerate; bring to room temperature and re-whip before using.
How Do I Get Super White Frosting?
Use clear vanilla if you have it and whip the butter until pale before adding sugar. A tiny drop of violet gel can neutralize yellow tones, but that’s optional.
Why Did My Cake Sink in the Middle?
Usually it’s from underbaking, opening the oven door too early, or too much leavening. Measure carefully, avoid peeking in the first 20 minutes, and bake until the center is fully set.
Can I Reduce the Sugar?
In the cake, you can reduce sugar by about 1/4 cup without affecting structure too much, but texture and moisture may change slightly.
In the frosting, start with 2 1/2 cups powdered sugar and adjust to taste.
Final Thoughts
Confetti sheet cake is pure nostalgia with a homemade touch. It’s easy to bake, simple to decorate, and always welcome at the table. With a tender crumb, creamy frosting, and cheerful sprinkles, it turns any moment into a small celebration.
Keep this recipe handy—you’ll use it all year long.
Ingredients
Method
- Prep the pan and oven: Heat the oven to 350°F (175°C). Grease a 9x13-inch metal baking pan and line the bottom with parchment for easy removal.
- Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, baking soda, and salt until evenly combined.
- Combine wet ingredients: In a separate bowl, whisk melted butter, oil, eggs, buttermilk, milk, vanilla, and almond extract until smooth.
- Make the batter: Pour the wet mixture into the dry ingredients. Whisk gently until just combined with no dry streaks. Do not overmix.
- Fold in sprinkles: Using a spatula, fold in the rainbow jimmies. Mix lightly to prevent color bleeding.
- Bake: Spread the batter evenly in the prepared pan. Bake 25–32 minutes, or until the top springs back and a toothpick comes out clean or with a few moist crumbs.
- Cool completely: Place the pan on a rack and let the cake cool fully before frosting, about 1 hour.
- Make the frosting: Beat the softened butter on medium-high until creamy and pale, about 2 minutes. Add powdered sugar in 2–3 additions, mixing on low at first, then increasing speed until fluffy.
- Adjust texture: Add heavy cream, vanilla, and a pinch of salt. Beat 1–2 minutes until smooth, light, and spreadable. Add more cream a teaspoon at a time if needed.
- Frost and decorate: Spread frosting over the cooled cake using an offset spatula. Add extra sprinkles on top. Slice into squares and serve.
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Sumayya is a home cook and recipe creator who shares simple, flavorful recipes made for everyday cooking. She believes good food should be easy, comforting, and enjoyed by everyone.
