Big Batch Confetti Cake

My kitchen still smells like vanilla and celebration whenever I bake this cake. Last summer, my daughter helped me fold in the sprinkles, and she was so delighted by how they scattered through the batter like edible confetti. Now every birthday request starts with 'can we make THE confetti cake' before anything else is discussed.

I made thirty cupcakes with this recipe for my nephews school party last spring. The teacher asked for the recipe before the last cupcake disappeared, which I consider the ultimate compliment. Now whenever I see rainbow sprinkles at the grocery store, I grab an extra bottle just in case.

Ingredients

• All-purpose flour: Provides structure and a tender crumb that holds up beautifully under generous frosting
• Granulated sugar: Sweetens and creates a moist texture, also helps the cake bake up with a lovely golden crust
• Baking powder and baking soda: Work together to give the cake its impressive rise and fluffy texture
• Fine sea salt: Balances sweetness and enhances all the vanilla flavors
• Whole milk: Creates richness and tenderness, and room temperature ingredients mix more evenly
• Vegetable oil: Keeps the cake incredibly moist and prevents it from drying out
• Unsalted butter: Melted butter adds incredible flavor that oil alone cannot achieve
• Large eggs: Provide structure and richness, and room temperature eggs incorporate better into batter
• Pure vanilla extract: The backbone of flavor, do not skip or substitute here
• Rainbow sprinkles: Use jimmies specifically in the batter to prevent color bleeding
• Unsalted butter for frosting: Room temperature butter whips into the smoothest, most luxurious buttercream
• Powdered sugar: Sifted sugar prevents lumps and creates silky smooth frosting
• Milk for frosting: Thins the buttercream to perfect spreadable consistency
• Vanilla extract for frosting: Makes the buttercream taste professional and irresistible
• Pinch of salt: Cuts the sweetness just enough so the buttercream does not feel cloying
• Extra sprinkles: For decorating the top and making it look absolutely festive

Instructions

Prepare your oven and pans:

Preheat your oven to 350°F (175°C) and generously grease two 9x13-inch baking pans, then line them with parchment paper for easy removal later.

Whisk together all your dry ingredients:

In a large bowl, combine the flour, sugar, baking powder, baking soda, and salt, whisking thoroughly to ensure everything is evenly distributed.

Mix your wet ingredients separately:

In another large bowl, whisk together the milk, vegetable oil, melted butter, eggs, and vanilla extract until completely smooth and emulsified.

Combine wet and dry ingredients:

Pour the wet mixture into the dry ingredients and mix gently until just combined, being careful not to overmix or the cake could become tough.

Fold in the rainbow sprinkles:

Gently fold in the sprinkles with a spatula, taking care not to overmix which could break the sprinkles and cause color bleeding.

Bake until perfectly done:

Divide the batter evenly between your prepared pans, smooth the tops, and bake for 30-35 minutes until a toothpick inserted in the center comes out completely clean.

Cool the cakes completely:

Let the cakes cool in their pans for 10 minutes, then carefully transfer them to wire racks to cool completely before frosting.

Make the buttercream frosting:

Beat the butter in a stand mixer on medium speed until creamy, about 2 minutes, then gradually add the powdered sugar while mixing well after each addition.

Finish the frosting:

Add the milk, vanilla, and salt, then beat on high speed for about 3 minutes until the buttercream becomes light and fluffy.

Frost and decorate generously:

Once the cakes are completely cool, spread a thick layer of buttercream over the top of each cake and decorate generously with additional sprinkles.

Save

This cake has become my go-to for every celebration because the smiles it creates are absolutely worth every step. Something about cutting into a slice flecked with rainbow colors just makes people happy before they even take a bite.

Making This For Special Occasions

I have found that this cake works beautifully for everything from casual potlucks to formal birthday parties. The recipe yields two 9x13-inch pans, so you can serve one at the party and stash the other in the freezer for unexpected celebrations later.

Frosting Like A Pro

The secret to bakery-worthy buttercream is patience during the whipping stage. Letting the frosting beat on high speed for the full three minutes incorporates tiny air bubbles that make it impossibly light and smooth.

Getting Ahead With This Recipe

You can bake the cake layers up to two days ahead if wrapped tightly in plastic and stored at room temperature. The buttercream also keeps beautifully in the refrigerator for up to a week, just bring it to room temperature and rewhip before using.

• Frosted cake actually tastes better the next day as flavors meld
• Unfrosted cake layers freeze beautifully for up to three months
• Bring all ingredients to room temperature before starting for best results

Save

Every slice of this cake feels like a little celebration, and that is exactly what baking should be about.

Recipe FAQs

→ What type of sprinkles work best in the batter?

Use jimmies (the long, thin sprinkles) in the cake batter. Nonpareils (the tiny round balls) will bleed their color into the batter, creating gray streaks instead of cheerful confetti. Save the nonpareils for decorating the finished frosting.

→ Can I make this as a layer cake instead of sheet cakes?

Absolutely. Divide the batter between three 9-inch round pans and reduce the baking time to 25-30 minutes. The buttercream amount is sufficient for filling and frosting a three-layer cake, though you may want to adjust based on how much frosting you prefer between layers.

→ How should I store the finished cake?

Store the frosted cake at room temperature for up to 3 days, covered with plastic wrap or a cake dome. The buttercream creates a protective seal that keeps the cake fresh. For longer storage, refrigerate for up to a week, though bring to room temperature before serving for the best texture.

→ Why do you use both oil and butter in the cake?

The combination gives you the best of both worlds—oil keeps the cake exceptionally moist and tender, while melted butter adds that rich, buttery flavor that pure oil cakes sometimes lack. Together, they create a velvety crumb that stays fresh longer than butter-only cakes.

→ Can I make the buttercream ahead of time?

Yes, make the buttercream up to 1 week in advance and store in an airtight container in the refrigerator. Let it come to room temperature, then give it a quick whip with your mixer to restore the fluffy texture before frosting your cooled cakes.

→ What's the best way to tell when the cake is done?

Insert a toothpick into the center of the cake—if it comes out clean or with just a few moist crumbs (not wet batter), the cake is ready. The tops should spring back lightly when touched, and the edges will be just beginning to pull away from the pan sides.