This homemade funfetti cake recipe makes one cheerful two-layer 8-inch birthday cake, serving about 10 to 12 people. The tender vanilla cake is filled with rainbow jimmies and finished with fluffy American-style vanilla buttercream, requiring about 30 to 35 minutes of preparation, 25 to 30 minutes of baking, and approximately 2 hours from start to finish.
Every slice has a soft, light crumb, a rich vanilla flavor, and colorful sprinkles tucked throughout the cake. Sour cream keeps the layers moist, while egg whites help create a delicate texture that pairs beautifully with sweet, creamy buttercream and a festive sprinkle topping.
Funfetti cake has a way of making an ordinary dessert feel like a celebration. The bright sprinkles create colorful little pockets throughout the vanilla crumb, so every slice looks festive before you even add the frosting.
This homemade version has the tender texture of a bakery cake without relying on a boxed mix. Sour cream adds moisture and a gentle richness, while three egg whites keep the crumb light rather than heavy.
The recipe is also wonderfully practical for birthdays and family gatherings. It makes two manageable 8-inch layers, serves about 10 to 12 people, and can be decorated simply with sprinkles or dressed up with piped buttercream borders.
Soft vanilla cake with a moist, delicate crumb
Rainbow color in every slice
Fluffy vanilla buttercream made with simple ingredients
A reliable choice for birthdays, showers, and cheerful celebrations
Ingredients You’ll Need
The cake begins with 2 1/4 cups of cake flour, which gives the layers a fine and tender texture. Combine it with 1 3/4 teaspoons of baking powder and 1/2 teaspoon of fine salt so the cake rises evenly and has balanced flavor.
For the rich base, use 3/4 cup of softened unsalted butter and 1 1/2 cups of granulated sugar. Three room-temperature egg whites provide structure without adding the deeper color or extra richness of yolks, allowing the sprinkles and pale crumb to stand out.
Pure vanilla extract, 1/2 cup of sour cream, and 3/4 cup of whole milk give the cake its familiar birthday-cake flavor and soft texture. The final ingredient is 2/3 cup of rainbow jimmies-style sprinkles, which are the long, narrow sprinkles that hold their shape best during baking.
For the buttercream, gather 1 cup of softened unsalted butter, 4 cups of sifted confectioners’ sugar, 1/4 cup of heavy cream or whole milk, 2 teaspoons of vanilla extract, and 1/4 teaspoon of fine salt. Keep extra sprinkles nearby for the finished decoration.
How to Make It Step-by-Step
Step 1: Heat the oven to 350°F (175°C) so it is fully ready when the batter is mixed. Grease two 8-inch round cake pans, line their bottoms with parchment, and lightly flour the sides to make releasing the layers easy.
Step 2: Add the cake flour, baking powder, and fine salt to a bowl and whisk until evenly combined. This distributes the leavening and salt before they meet the wet ingredients, helping each cake layer bake consistently.
Step 3: Place the softened butter and granulated sugar in a large mixing bowl. Beat them for about 3 to 4 minutes, until the mixture is noticeably paler and fluffy, because this creaming step helps create a lighter cake.
Step 4: Add the egg whites gradually, beating well after each addition so they blend into the butter mixture instead of separating. Beat in the vanilla extract, then mix in the sour cream until the wet mixture looks smooth and creamy.
Step 5: Add the dry ingredients in three additions, alternating each portion with some of the room-temperature milk. Mix only until the ingredients are combined, since extra mixing after the flour is added can make the layers less tender.
Step 6: Sprinkle the rainbow jimmies over the finished batter and fold them in gently by hand with a spatula. Work quickly and carefully, then divide the batter evenly between the prepared pans so the sprinkles have less time to bleed.
Step 7: Bake the pans for 25 to 30 minutes. The cakes are ready when their centers spring back lightly and a toothpick inserted in the middle comes out with a few moist crumbs rather than wet batter.
Step 8: Let the cakes cool in their pans for about 10 minutes before turning them onto a cooling rack. Allow both layers to cool completely, since warm cake can soften the buttercream and make assembly difficult.
Step 9: Make the frosting by beating the softened butter until smooth, then gradually adding the sifted confectioners’ sugar. Add the cream or milk, vanilla, and salt, and beat for 3 to 5 minutes until the buttercream is light, airy, and easy to spread.
Step 10: If the layers have domed, trim them lightly with a serrated knife so they stack neatly. Put one layer on a serving plate, spread frosting over it, add the second layer, cover the top and sides with buttercream, and decorate with extra sprinkles.
Pro Tips for Colorful, Tender Layers
Room-temperature ingredients matter more than many bakers expect. Soft butter blends properly with the sugar, room-temperature egg whites incorporate more smoothly, and sour cream and milk help the batter mix evenly without chilling the fat.
Choose rainbow jimmies instead of nonpareils for the cake batter. Jimmies generally retain their color and shape better in the oven, while tiny nonpareils can dissolve or bleed, leaving streaks in the crumb.
Fold in the sprinkles only after the batter is finished, and bake soon afterward. Gentle folding protects the sprinkles from breaking, while a short wait reduces the chance of the colors spreading through the pale batter.
For even layers, use a kitchen scale to divide the batter between the pans if you have one. If you are measuring by sight, spoon the batter into each pan in several portions and compare the levels before baking.
Do not judge doneness by color alone. The best signs are lightly springing centers and a toothpick with a few moist crumbs, which indicate a baked cake that should remain soft after cooling.
Buttercream, Assembly, and Decoration
Sift the confectioners’ sugar before adding it to the butter. This removes lumps and makes the frosting smoother, especially when you want a clean finish across the sides of the cake.
Begin frosting with a thin crumb coat, if desired. Spread a light layer over the stacked cake, chill it briefly to hold loose crumbs in place, then apply the remaining buttercream for a smoother final coating.
A simple sprinkle finish looks wonderfully festive. Press extra rainbow jimmies around the bottom edge, scatter them over the top, or create a colorful border by gently applying them to the freshly frosted sides.
For neat slices, use a long sharp knife and wipe the blade between cuts. Let a refrigerated cake sit toward room temperature before serving so the buttercream softens and the vanilla flavor becomes more pronounced.
Storage and Serving Suggestions
Keep the completed cake covered so the layers do not dry out or absorb refrigerator odors. Because the buttercream contains butter and dairy, refrigerating the cake is the safest choice for longer storage, especially in a warm kitchen.
Before serving, allow the cake to come back toward room temperature for a softer crumb and creamier frosting. The cake is especially appealing with cold milk, coffee, or a scoop of vanilla ice cream.
You can prepare the cake layers ahead of assembly once they have cooled completely. Wrap them well and keep them protected from air, then frost and decorate when you are ready to turn them into a celebration cake.
This recipe is designed as one two-layer 8-inch cake and yields about 10 to 12 servings. For a party, cut slim wedges first and return for additional slices as needed, since the colorful design makes the cake feel generous on the plate.
Homemade Funfetti Cake Recipe
A soft vanilla cake packed with rainbow jimmies, layered and covered with fluffy vanilla buttercream. This festive two-layer cake is perfect for birthdays, showers, school celebrations, and any occasion that calls for extra color.
Heat the oven to 350°F (175°C). Grease two 8-inch round cake pans, line the bottoms with parchment, and lightly flour the sides.
Whisk the cake flour, baking powder, and fine salt together in a medium bowl.
Beat the softened butter and granulated sugar for 3 to 4 minutes, until pale, smooth, and fluffy.
Add the egg whites gradually, beating after each addition, then mix in the vanilla extract. Stir in the sour cream until the mixture is smooth.
Add the dry mixture to the butter mixture in three additions, alternating with the milk. Mix only until the batter comes together, scraping the bowl as needed.
Fold in the rainbow jimmies gently by hand. Divide the batter evenly between the prepared pans and bake immediately.
Bake for 25 to 30 minutes, until the centers spring back lightly and a toothpick comes out with a few moist crumbs. Cool the cakes in their pans for about 10 minutes, then turn them onto a rack and cool completely.
For the buttercream, beat the softened butter until smooth. Gradually add the sifted confectioners’ sugar, then add the cream or milk, vanilla, and salt.
Beat the frosting for 3 to 5 minutes, until light and fluffy. Level the cake layers if necessary, place one layer on a serving plate, spread buttercream over it, add the second layer, and frost the top and sides.
Finish the cake with extra rainbow sprinkles. Chill briefly if needed for cleaner slices, then serve at room temperature for the softest buttercream and crumb.
Notes
Use rainbow jimmies rather than nonpareils because jimmies hold their color and shape better. Keep the butter, egg whites, sour cream, and milk at room temperature, avoid overmixing after adding flour, and fold in the sprinkles at the very end. Store the finished cake covered at room temperature for a short serving period or refrigerate it for longer storage, bringing it back toward room temperature before serving.
Final Thoughts
This homemade funfetti cake recipe brings together everything a celebration cake should have: a soft vanilla crumb, bright rainbow sprinkles, and a generous layer of fluffy buttercream. The preparation is straightforward, but the finished cake looks joyful enough for a centerpiece.
For the best result, start with room-temperature ingredients, use rainbow jimmies, mix the batter gently, and fold in the sprinkles at the very end. Once the layers are cool, the buttercream and decorations come together quickly, making this a dependable choice for birthdays and special occasions.
Serve each slice with plenty of frosting and let the colorful crumb do the talking. It is a cheerful, nostalgic dessert that tastes homemade in the very best way.
