Gluten-Free Funfetti Birthday Cake

5 from 1 vote

This gluten free birthday cake is a classic vanilla layer cake with rainbow sprinkles and fluffy buttercream, made for true birthday-style celebrating. It’s baked into sturdy yet tender cake layers that stack cleanly, frost smoothly, and slice without crumbling or falling apart. A well-balanced gluten-free flour blend paired with the right mixing method creates a moist, nostalgic crumb with no grit, so the finished cake tastes just as good to everyone at the table–not just those eating gluten free!

Prep Time10

Cook Time40

Total Time55

Course: Dessert

Cuisine: American

Diet: Gluten Free

Keyword: gluten-free birthday cake, gluten-free funfetti cake

Method: Oven

Servings:

Equipment

Ingredients

3 cups gluten-free flour (360g) I use King Arthur's Measure for Measure
2 cups sugar (400g)
2 sticks butter (1 cup 227g)
4 large eggs
2 large egg whites
3/4 cup whole milk
1/4 cup buttermilk
1/3 cup sour cream
1 tbsp + 2 tsp gluten-free baking powder
3 tsp vanilla extract
3/4-1 cup sprinkles

Buttercream Frosting

1 cup unsalted butter 2 sticks
1/3 cup heavy whipping cream
4.5-5 cups confectioners sugar sifted
2 tsp clear vanilla extract

Instructions

Gluten-Free Cake

Preheat the Oven:Preheat your oven to 350°F (175°C). Prepare (2) 8-inch or (3) 6-inch round cake pans by greasing them and lining the bottoms with parchment paper. Set aside.
Sift the Dry Mix: In a separate bowl, sift together the gluten-free flour and baking powder. Set aside
Cream Butter & Sugar: In a large mixing bowl, cream together the softened butter and sugar 3-5 minutes until light and fluffy using a hand mixer or stand mixer. Creaming the butter and sugar is a crucial step in getting the perfect texture. Add the eggs and egg whites one at a time, beating well after each addition. Stir in the vanilla extract.
Mix the Milk and Sour Cream: In another bowl, combine the whole milk, buttermilk, and sour cream.
Prepare the Batter: Add the dry ingredients to the butter mixture in three additions, alternating with the wet ingredients, starting and ending with the dry ingredients. Mix until just combined, being careful not to overmix. Gently fold in the sprinkles until evenly distributed throughout the batter.
Add Batter To Pans: Divide the batter evenly among the prepared cake pans. Smooth the tops with a spatula to even out the batter.
Filling Cake Pans Correctly: For an 8 or-9 inch round cake pan, you typically want to fill it no more than two-thirds to three-quarters full, depending on the recipe. When filling a 6-inch cake pan with batter, you typically want to fill it to about halfway
Bake: Place the pans in the preheated oven and bake for 35-40 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
Cool: Remove the cakes from the oven and let them cool in the pans for 10 minutes. After 10 minutes, carefully remove the cakes from the pans and transfer them to wire racks to cool completely.
Optional Step: Freeze the cake for easier decorating! You can skip right ahead to step 11, but if you want to use my trick for better taste and easier decorating, wrap your cooled cakes in plastic wrap and freeze for 6-24 hours. Once frozen, move on to the assembly. Then, cover your frosted cake and let it thaw at room temperature for 2-4 hours before serving. Don’t refrigerate or it can dry out.
Assemble the Cake: Once the cakes are completely cooled, you can assemble the cake by layering them with your favorite frosting between each layer. Optionally, you can frost the top and sides of the cake with more frosting.
Sprinkle by Hand: Place the cake over a baking sheet or large plate to catch any excess sprinkles. With clean hands, gently press the sprinkles onto the sides of the cake, rotating the cake as you go to ensure even coverage.

Buttercream Icing

In a stand mixer, add the butter and beat together with the paddle attachment or use a hand mixer on medium speed until smooth and creamy. Add the vanilla extract to the butter and continue to beat until well combined.
Gradually add the confectioners’ sugar to the butter, one cup at a time. Start the mixer on low speed to avoid a sugar shower. Scrape down the sides of the bowl as needed. Add the heavy cream slowly. Check the consistency of the buttercream. If it’s too thick, add a little more heavy cream, one tablespoon at a time, until you reach your desired consistency. If it’s too thin, add a bit more confectioners’ sugar.
TIP: If you want bright white icing, add a very small touch of purple food coloring. This cancels out the yellow tint and makes it super white.
If you want enough icing to decorate the top, I recommend doubling the buttercream recipe.

Notes

Pan Size Options

This gluten-free funfetti cake recipe works well for multiple pan sizes:

Two 8-inch round pans: Fill each about two-thirds to three-quarters full
Three 6-inch round pans: Fill about halfway
Sheet cake: Use a standard sheet pan and adjust bake time, checking for doneness.

Expert Tips for Success

Use room-temperature ingredients so the batter mixes evenly and bakes up smooth. Measuring flour carefully matters too–a kitchen scale gives the most consistent results.
Freeze the cake layers for easier decorating. Wrap fully cooled layers tightly and freeze for 6-24 hours. Frozen layers are easier to stack, create fewer crumbs, and often taste even better once thawed.
Keep the funfetti theme going. If someone in your house loves celebrating with a sweet birthday breakfast, my birthday cake pancakes are a fun way to carry the celebration from morning to night!
How to avoid cake sink: Overfilling pans is one of the most common causes. Level the batter gently, tap pans to release air bubbles, avoid opening the oven door too early, and always check for doneness before removing the cakes.

Storage & Make-Ahead Tips

This cake is ideal for planning ahead. Bake and freeze the layers up to one month in advance, frost while frozen, then let the finished cake thaw at room temperature for 2-4 hours before serving.
Once frosted, the cake can be stored at room temperature for up to 3 days if covered well. If refrigerated due to heat or humidity, allow it to come to room temperature slowly before serving to avoid condensation on the frosting.

Nutrition