If you’re looking for a delicious and festive cake that will steal the spotlight at any celebration, look no further than this Funfetti Birthday Sheet Cake. This soft, fluffy vanilla cake is bursting with colorful rainbow sprinkles and topped with a silky, creamy buttercream frosting. Whether you’re celebrating a birthday, hosting a party, or just craving something sweet, this cake is guaranteed to impress. It’s easy to slice, making it perfect for large gatherings, and it’s a crowd favorite that everyone will enjoy.

What Is Funfetti Birthday Sheet Cake?
Funfetti Birthday Sheet Cake is a classic celebration dessert made from a light and airy vanilla cake loaded with colorful rainbow sprinkles. The term “Funfetti” refers to the sprinkles mixed into the batter, creating a festive, confetti-like appearance once baked. This cake is frosted with a smooth, fluffy vanilla buttercream that complements the sweetness of the cake perfectly. With a tender crumb and rich flavor, it’s a perfect treat for any occasion.
The origin of Funfetti cake can be traced back to the 1980s, thanks to a popular cake mix brand. Over the years, it has become a go-to choice for birthdays and celebrations, known for its playful appearance and fun flavor. Today, homemade Funfetti cake recipes like this one continue to be a hit at parties, offering a homemade touch that’s even better than the store-bought versions.
Ingredients for Funfetti Birthday Sheet Cake
To make this Funfetti Birthday Sheet Cake, you’ll need the following ingredients. The quantities listed will make enough batter for a standard 9×13 sheet cake, serving around 16-20 people.
Funfetti Cake
- 2 ½ cups (310g) all-purpose flour
- 2 tsp baking powder
- ½ tsp baking soda
- ½ tsp salt
- 1 cup (226g) unsalted butter, softened
- 1 ¾ cups (350g) granulated sugar
- 4 large eggs (room temperature)
- 1 tbsp vanilla extract (or 2 tsp vanilla + 1 tsp almond extract for a “bakery” flavor)
- 1 cup (240ml) buttermilk (room temperature)
- ½ cup (100g) rainbow jimmies sprinkles (not nonpareils—these can bleed during baking!)
Fluffy Vanilla Frosting
- 1 cup (226g) unsalted butter, softened
- 3 ½ – 4 cups (420–480g) powdered sugar, sifted
- 2–3 tbsp milk or heavy cream
- 1 tbsp vanilla extract (or 1 ½ tsp vanilla + ½ tsp almond extract for an extra flavorful kick)
- Pinch of salt
- Extra sprinkles for decorating
Step-by-Step Directions for Funfetti Birthday Sheet Cake

Step 1: Prepare the Pan and Preheat the Oven
Start by preheating your oven to 350°F (180°C). Grease or line a 9×13-inch baking pan with parchment paper to ensure that your cake comes out easily once baked.
Step 2: Mix Dry Ingredients
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set the mixture aside while you work on the wet ingredients.
Step 3: Cream Butter and Sugar
In a large bowl, cream together the unsalted butter and granulated sugar using an electric mixer on medium speed. Beat for about 3-4 minutes until the mixture is pale and fluffy.
Step 4: Add Eggs and Flavor
Add the eggs one at a time, making sure to mix well after each addition. Once the eggs are fully incorporated, stir in the vanilla extract. For an enhanced flavor, you can also add almond extract to both the cake and frosting.
Step 5: Combine Wet and Dry Ingredients
Add the dry ingredients to the wet mixture in three parts, alternating with the buttermilk. Start and end with the dry ingredients. Mix just until combined, being careful not to overmix the batter.
Step 6: Fold in the Sprinkles
Gently fold the rainbow sprinkles into the batter using a spatula. Be careful not to overmix, as you don’t want the sprinkles to bleed into the batter.
Step 7: Bake the Cake
Pour the batter into the prepared pan, spreading it out evenly. Bake for 28–34 minutes or until a toothpick inserted into the center comes out clean. Let the cake cool completely before frosting.
Step 8: Make the Frosting
To make the frosting, beat the unsalted butter until smooth and creamy. Gradually add the powdered sugar, mixing well after each addition. Stir in the vanilla extract, salt, and enough milk or heavy cream to achieve a light and fluffy consistency. Beat for about 2-3 minutes until the frosting is smooth and spreadable.
Step 9: Frost and Decorate
Once the cake is completely cooled, spread the frosting generously over the surface of the cake. Top with additional rainbow sprinkles to give it that festive, party-ready look!
Variations of Funfetti Birthday Sheet Cake
While the classic Funfetti Birthday Sheet Cake is perfect as it is, there are several fun ways to switch it up based on personal preferences. Here are a few variations you can try:
| Variation | Change |
|---|---|
| Bakery Flavor | Add ½ tsp almond extract to both the cake and frosting for a bakery-style flavor. |
| Extra Moist | Replace 2 tbsp of butter with 2 tbsp of oil to make the cake even more moist. |
| Chocolate Funfetti | Add ¼ cup of cocoa powder and 2 tbsp extra buttermilk for a chocolate twist on this cake. |
| Confetti Layers | Bake the cake in two 8-inch round pans to create a layered Funfetti cake. |
| Gluten-Free | Use a 1:1 gluten-free flour substitute and add an extra 1 tbsp of buttermilk for a gluten-free version of this cake. |
FAQs About Funfetti Birthday Sheet Cake
Q: Can I make this cake ahead of time?
A: Yes! You can bake the cake ahead of time and store it at room temperature (covered) for up to two days. The frosting can also be made in advance and stored in the fridge for up to 3 days. Just bring it to room temperature before frosting the cake.
Q: Can I use nonpareil sprinkles instead of jimmies?
A: While nonpareils are cute, they tend to bleed into the cake batter when baked, creating streaks of color. It’s best to use jimmies sprinkles for a neat and vibrant effect.
Q: Can I make this cake into cupcakes instead of a sheet cake?
A: Yes! You can bake this batter into cupcakes. Simply adjust the baking time to 18-22 minutes or until a toothpick inserted into the center comes out clean.
Q: How can I store the leftover cake?
A: Store any leftover cake at room temperature for up to 2 days. For longer storage, refrigerate the cake for up to 5 days or freeze it for up to 2 months (unfrosted).
Conclusion
This Funfetti Birthday Sheet Cake is a timeless recipe that brings joy and color to any celebration. The soft and fluffy vanilla cake, combined with the sweet, creamy frosting, makes it a delightful treat that’s sure to please any crowd. Whether you’re celebrating a birthday, an anniversary, or just enjoying a weekend treat, this cake will be the star of the show. With its simple ingredients and easy-to-follow instructions, you’ll have a stunning, crowd-pleasing dessert ready in no time. Enjoy your Funfetti cake and get ready for the compliments to roll in!
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