If you're looking for the sheet cake for your next big birthday party (or heck, any party), then this funfetti sheet cake is going to be your new go-to! This soft and fluffy vanilla funfetti sheet cake is packed with rainbow sprinkles and then covered in the creamiest vanilla bean buttercream. The cake is super soft thanks to the perfect combo of butter and neutral oil!
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Who can say no to a confetti sheet cake? Not me! Look, funfetti/confetti/whatever you want to call it IS a flavor, I stand by that.
I based this confetti cake recipe on my mini chocolate chip sheet cake. When I was first testing out vanilla sheet cakes, I found that my cake batter was slightly too loose. While that makes for a super soft and moist cake, it does mean mix-ins (like rainbow sprinkles or chocolate chips!) are more likely to sink when baking.
If you're more of a chocolate vibes gal (me too), you can try my chocolate sheet cake with vanilla frosting instead.
Getting a Soft & Moist Cake
To rectify this, I slightly increased the flour and decreased the buttermilk. And now - perfect rainbow sprinkles that stay in place! I also decided to add a touch of cornstarch to make this cake softer and tender, as we're losing some of that soft texture from removing some of the buttermilk.
The cake is finished with the very best vanilla bean buttercream! You could definitely swap it out for Oreo frosting or a classic chocolate fudge frosting.
Grab Your Ingredients
- Rainbow sprinkles 🌈 Make sure you're using long-stranded sprinkles and not those little balls (called nonpareils). When testing out different funfetti cakes, I've found long-stranded sprinkles work best and don't bleed too much into the cake.
- Oil makes the cake extra soft 🥣 Most vanilla cakes use just butter, but I do an equal amount of butter and neutral oil. The butter gives us that great flavor, while the oil provides softness and moisture. I recommend using something like vegetable oil or canola oil!
Let's Make This Cake
- In a stand mixer fitted with the paddle attachment, beat the butter, sugar, and oil together until light and fluffy.
- Add the eggs one at a time. Then mix in the vanilla extract.
My Test Kitchen Tip 👩🏻🍳: When adding ingredients to your mixing bowl, I recommend stopping the mixer and scraping down the sides and bottom of the bowl with a rubber spatula. That way, your cake batter is being evenly mixed!
- Whisk all of the dry ingredients in a separate bowl. Add the dry ingredients in 3 additions, alternating with the butter milk.
- Now for the fun part - stir in your rainbow sprinkles!
- Pour the funfetti cake batter into a greased and lined 9x13-inch sheet pan. Bake in the oven. Let the cake cool completely before you start making the frosting.
- In a stand mixed fitted with the paddle attachment, beat the butter with the powdered sugar until light and fluffy. Add the vanilla bean paste or extract along with the salt. Pour in your heavy cream and beat until light and creamy. Frost your cake and enjoy!
Decorating Your Cake Like a Pro
Here are a few simple ways you can decorate your sheet cake!
- Use a small offset spatula to spread the vanilla frosting all over the cake. Use a small spoon to create swoops and swirls. Finish with a smattering of sprinkles and you're good to go! You could also fold in rainbow sprinkles into the buttercream before spreading over your cake.
- Keep the cake in the baking pan. Spread a thin layer of frosting on top of the cake, making sure you reach the edges. Place remaining frosting in a piping bag with an open star tip. Pipe a shell border around the edges and finish with sprinkles.
Made This Recipe?
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Thank you!
Ella
Recipe
Birthday Funfetti Sheet Cake with Vanilla Buttercream
Equipment
- 9x13-inch cake pan
- Stand Mixer
- Kitchen Scale
- Measuring Spoons
- Bowl
- Whisk
- Rubber Spatula
- small offset spatula
Ingredients
Funfetti Sheet Cake
- ⅓ cup (75 grams) unsalted butter room temperature
- 1 ⅔ cup (333 grams) white sugar
- ¼ cup (50 ml) neutral oil
- 4 large eggs room temperature
- 3 teaspoons vanilla extract
- 2 teaspoons baking powder
- 2 tablespoons cornstarch
- 1 ½ teaspoons kosher salt
- 3 cups (360 grams) all-purpose flour
- ½ cup (113 ml) buttermilk room temperature
- ½ cup (182 grams) rainbow sprinkles
Vanilla Buttercream
- 2 sticks (226 grams) unsalted butter room temperature
- 1 tablespoon vanilla bean paste can swap out for extract
- ¼ teaspoon kosher salt
- 4 cups (480 grams) powdered sugar
- ¼ cup (56 ml) heavy cream or whole milk
Instructions
- Preheat the oven to 350℉/175℃. Grease and line a 9x13-inch cake pan with parchment paper.
- In a stand mixer fitted with the paddle attachment, beat the room temperature butter with the oil and sugar until creamy on medium speed. This will take about 2-3 minutes, and it'll look a bit grainy and fluffy.⅓ cup (75 grams) unsalted butter , 1 ⅔ cup (333 grams) white sugar, ¼ cup (50 ml) neutral oil
- Add the eggs one at a time, beating well and scraping the bowl after each addition.4 large eggs
- Mix in the vanilla extract.3 teaspoons vanilla extract
- In a small bowl, whisk together the flour with the baking powder, cornstarch, and salt.2 teaspoons baking powder, 2 tablespoons cornstarch, 1 ½ teaspoons kosher salt, 3 cups (360 grams) all-purpose flour
- Add ⅓ of the flour mixture, then mix on low. Add ½ the buttermilk. Repeat once more, then end with the flour mixture.½ cup (113 ml) buttermilk
- Gently stir in the rainbow sprinkles.½ cup (182 grams) rainbow sprinkles
- Pour the cake batter into the prepared pan.
- Bake for 33-42 minutes, or until a toothpick inserted comes out clean. Let the cakes cool in the pan for 10-15 minutes before removing and letting them cool completely on wire cooling racks.
- In a stand mixer fitted with the paddle attachment, or in a large bowl with a hand held mixer, combine the room temperature butter with the confectioners' sugar, salt, and vanilla bean paste on low speed.2 sticks (226 grams) unsalted butter, 1 tablespoon vanilla bean paste, 4 cups (480 grams) powdered sugar, ¼ teaspoon kosher salt
- Increase the speed to medium-high and beat for 2-3 minutes, until light and fluffy.
- If the frosting isn't as creamy as you would like, add in the heavy cream or milk and beat on medium speed until spreadable. You might not need all of it!¼ cup (56 ml) heavy cream
- Frost your cooled cake and add more sprinkles - enjoy!
Save This Recipe! 💌
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Nicole says
Made this for my grandkids birthday celebration. Didn’t put the sprinkles but instead spread a couple of tbsp of strawberry jam on top of cake. Popped in deep freeze for a bit and then I put the vanilla buttercream on top. Delicious light sponge cake & lots of yummy buttercream icing. 5 stars & so easy to make. Will be redoing this often.