Rainbow Layer Cake : 6 Stunning Layers of Color & Vanilla Buttercream Frosting

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If you have ever dreamed of slicing into a cake and revealing a full spectrum of color, this Rainbow Layer Cake is exactly what you need to make. This recipe delivers six perfectly soft and fluffy cake layers, each tinted in a vibrant gel color, stacked high with silky vanilla buttercream frosting and finished with rainbow sprinkles. Whether you are baking for a birthday party, a family celebration, or simply want to bring some joy to your kitchen, this cake is guaranteed to impress every single guest at the table.

Beyond its stunning visual impact, this cake is built on a classic, reliable vanilla cake batter that bakes up tender and moist every single time. The vanilla buttercream is rich, creamy, and perfectly balanced. Together, they create a dessert that is as delicious as it is beautiful. Let us walk through everything you need to make this spectacular cake from start to finish.

Ingredients

For the Cake Batter

For the Gel Colors

For the Vanilla Buttercream Frosting

For Decoration

• 1 teaspoon rainbow sprinkles

Equipment You Will Need

• Electric stand mixer – essential for creaming butter and making buttercream
• Oven – for baking the six cake layers
• Baking sheets – useful for transporting cake pans in and out of the oven
• Pots – for any prep needs
• Frying pans – handy in the kitchen setup
• Kitchen utensils – including offset spatulas and rubber spatulas
• Cutting board – for prep and serving
• Chef’s knives – for slicing clean cake slices
• Measuring cups and spoons set – for precise measurements
• Mixing bowls – you will need at least 6 medium bowls for the colored batters
• Kitchen scale – recommended for accurate gram measurements

Step-by-Step Instructions

Step 1 – Preheat and Prepare the Pans

Preheat your oven to 350 degrees F. Lightly butter the bottom of six 8-inch cake pans and place an 8-inch round of parchment paper on the bottom of each. If you do not have six cake pans, you can bake the layers in multiple rounds.

Step 2 – Combine the Dry Ingredients

In a large mixing bowl, whisk together the flour, salt, and baking powder using your kitchen utensils. Set this bowl aside while you prepare the wet ingredients.

Step 3 – Whisk the Eggs

In a separate mixing bowl with a spout, whisk together the 4 large eggs, 2 egg whites, and the vanilla extract until fully combined. Set aside.

Step 4 – Cream the Butter and Sugar

Add the room temperature butter and sugar to the bowl of your electric stand mixer fitted with the paddle attachment. Mix on medium speed for 9 to 10 minutes until the mixture turns white in color and becomes light and fluffy. Do not rush this step. The extended mixing time creates the airy texture that makes this cake so tender.

Step 5 – Add the Eggs

With the mixer running on low, slowly stream in the whisked eggs and vanilla mixture. Turn off the mixer and scrape down the sides and bottom of the bowl with a rubber spatula from your kitchen utensils set. Mix one more time on low to ensure everything is well incorporated.

Step 6 – Alternate Dry and Wet Ingredients

Add one-third of the dry ingredients to the mixing bowl and mix on low speed to combine. Slowly stream in half of the buttermilk. Continue alternating the dry ingredients and buttermilk, ending with the dry ingredients, until everything is fully combined. Scrape down the sides and bottom of the bowl thoroughly and mix once more to make sure the batter is uniform.

Step 7 – Distribute and Color the Batter

Use your measuring cups to evenly distribute approximately 1 1/2 cups (280g) of batter into each of six medium mixing bowls. Add one gel color to each bowl and stir well with a spoon until the color is fully and evenly mixed into the batter. You will have red, orange, yellow, green, blue, and purple batters.

Step 8 – Bake the Layers

Pour each bowl of colored batter into its prepared cake pan. Use a small offset spatula from your kitchen utensils to spread the batter evenly to the edges of the pan. Place the pans on your baking sheets and bake three pans at a time in your preheated oven for 17 minutes, until the tops spring back when lightly touched and the cake begins to pull away from the sides of the pans.

Step 9 – Cool the Layers

Allow each pan to cool on a wire rack for 5 minutes. Then turn each pan over and remove the layers. They should release cleanly and easily. Let all six layers cool completely on the wire rack before assembling. Repeat the baking process if you are working in batches.

Step 10 – Make the Vanilla Buttercream

In the bowl of your stand mixer fitted with the paddle attachment, beat the butter on medium speed for about 2 minutes until smooth. Add the powdered sugar and mix on low until combined, then increase the speed to medium-high and continue mixing for 3 to 4 minutes until the frosting is white and fluffy. Add the milk and vanilla, mix on low to combine, then increase to medium speed and mix for another 30 seconds until perfectly fluffy.

Step 11 – Stack and Frost the Layers

Place the purple cake layer right side up on a large plate or cardboard cake round at least 2 inches larger than the cake. Use an offset spatula or butter knife from your kitchen utensils set to spread about 1/2 cup of frosting evenly over the layer. Add the blue layer and spread another 1/2 cup of frosting on top. Continue with the green, yellow, and orange layers. Place the red cake layer upside down on top so that the cake has a flat, smooth top. Make sure all layers are centered and level.

Step 12 – Apply the Crumb Coat

Spread about 1 cup of frosting over the top and sides of the entire cake using your offset spatula, creating a thin and even layer. You should be able to see the cake through this layer. This thin coat is called the crumb coat and it seals in any loose crumbs so your final layer of frosting stays perfectly clean.

Step 13 – Chill and Apply the Final Frosting

Place the cake uncovered in the freezer for 10 to 15 minutes or in the refrigerator for 20 to 30 minutes until the crumb coat is fully set. Then remove the cake and apply a generous, thick final layer of frosting over the top and sides. Use the offset spatula to smooth the sides and top into a clean, professional finish.

Step 14 – Decorate

Hold the cake with one hand and slightly tilt it so you can gently press rainbow sprinkles along the bottom border of the cake. Fill a piping bag fitted with a large star tip with the remaining buttercream and pipe 10 to 12 rosettes along the top edge of the cake. Sprinkle the tops of the rosettes with additional rainbow sprinkles.

Step 15 – Final Chill and Serve

Place the finished cake in the freezer for 20 to 30 minutes before cutting. Use a hot, sharp chef’s knife to cut perfectly clean and beautiful slices that reveal the stunning rainbow interior.

Pro Tips for the Best Rainbow Layer Cake

• Always use room temperature butter and eggs. Cold ingredients do not cream properly and will result in a dense cake.
• Use a kitchen scale to weigh your batter portions for perfectly even layers.
• Use gel food coloring, not liquid. Gel colors are far more concentrated and will not thin out your batter.
• Do not skip the crumb coat. It makes a significant difference in the cleanliness of the final frosting layer.
• A hot knife is the secret to clean slices. Run your chef’s knife under hot water, wipe it dry, and slice immediately.
• Use your measuring cups and spoons set for all ingredients to ensure consistency.

Storage Instructions

Once assembled and decorated, store the Rainbow Layer Cake in the refrigerator until you are ready to serve it. Pull the whole cake out of the fridge a few hours before cutting to allow it to come back to room temperature, which makes slicing much easier and improves the texture.

For leftover slices, place them on a plate or baking sheet and freeze for 10 to 15 minutes until solid. Then wrap each slice twice in plastic wrap and store in the freezer for up to one month.

Frequently Asked Questions

Can I make the Rainbow Layer Cake layers ahead of time?

Yes. You can bake all six cake layers up to two days in advance. Once they are completely cooled, wrap each layer tightly in plastic wrap and store at room temperature or in the refrigerator until you are ready to assemble.

What is the best way to get vibrant colors in the Rainbow Layer Cake?

Always use professional-grade gel food coloring such as Americolor. These gels are highly pigmented and will give you bold, vivid colors without altering the consistency of your batter.

Can I use a hand mixer instead of a stand mixer?

You can use an electric hand mixer for both the cake batter and the buttercream. Just be aware that creaming the butter and sugar will take a bit longer with a hand mixer than with a stand mixer.

How do I prevent the Rainbow Layer Cake from leaning?

Make sure each layer is fully cooled before assembling. Warm layers will cause the frosting to melt and the cake to slide. Also, chill the cake in the freezer between the crumb coat and the final frosting to keep everything stable and upright.

Can I substitute buttermilk in this recipe?

Yes. If you do not have buttermilk on hand, you can make a quick substitute by adding 1 tablespoon of white vinegar or lemon juice to 1 cup of regular milk. Let it sit for 5 minutes before using.

How many servings does this Rainbow Layer Cake make?

This cake yields approximately 12 to 16 servings depending on how thick you slice it, making it ideal for parties and gatherings.

Make This Rainbow Layer Cake Today

This Rainbow Layer Cake is one of the most rewarding baking projects you can take on. The process is straightforward, the results are absolutely breathtaking, and every slice you serve will make someone smile. Follow this recipe step by step, trust the process, and you will have a masterpiece on your hands. Save this recipe to your Pinterest board and share it with your friends and family. You deserve to celebrate in full color.

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Rainbow Layer Cake : 6 Stunning Layers of Color & Vanilla Buttercream Frosting

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A stunning 6-layer Rainbow Layer Cake made with vibrant gel-colored vanilla cake layers, silky vanilla buttercream frosting, and rainbow sprinkles. Perfect for birthdays and celebrations.

• Author: Sara
• Prep Time: 45 minutes
• Cook Time: 17 minutes
• Total Time: 2 hours
• Yield: 12 to 16 servings
• Category: Dessert
• Method: Baking
• Cuisine: American
• Diet: Vegetarian

Ingredients

Scale 1x2x3x

3 3/4 cups (450g) all-purpose flour

3 1/2 teaspoons baking powder

1 teaspoon salt

2 1/4 cups (500g) sugar

1 1/4 cups (282g) unsalted butter, room temperature

4 large eggs, room temperature

2 large egg whites, room temperature

1 1/2 tablespoons vanilla extract

1 1/2 cups (320g) buttermilk

1/2 teaspoon Americolor Gel Super Red

1/4 teaspoon Americolor Gel Lemon Yellow

1/4 teaspoon Americolor Gel Leaf Green

1/4 teaspoon Americolor Gel Royal Blue

1/2 teaspoon Americolor Gel Violet

1/4 teaspoon Americolor Gel Orange

2 1/2 cups (567g) unsalted butter, room temperature (for frosting)

5 cups (500g) powdered sugar

2 teaspoons vanilla extract (for frosting)

2 tablespoons 2% milk

1 teaspoon rainbow sprinkles

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Instructions

1. Preheat the oven to 350 degrees F. Butter six 8-inch cake pans and line the bottoms with parchment paper.

2. Whisk together the flour, salt, and baking powder in a large bowl and set aside.

3. In a separate bowl, whisk together the eggs, egg whites, and vanilla extract. Set aside.

4. Beat the butter and sugar in a stand mixer on medium speed for 9 to 10 minutes until white and fluffy.

5. With the mixer on low, stream in the whisked eggs and vanilla. Scrape down the bowl and mix again.

6. Alternate adding one-third of the dry ingredients and half of the buttermilk, ending with dry ingredients. Scrape down and mix until combined.

7. Divide the batter evenly into 6 bowls (about 1 1/2 cups each). Add one gel color to each bowl and stir to combine.

8. Pour each colored batter into its prepared pan and smooth the top. Bake 3 pans at a time for 17 minutes until the tops spring back when touched.

9. Cool pans on a wire rack for 5 minutes, then turn out the layers and cool completely.

10. Beat the butter for the frosting on medium speed for 2 minutes. Add powdered sugar and mix until white and fluffy, about 3 to 4 minutes. Add milk and vanilla and mix for 30 more seconds.

11. Stack the layers from purple to red, spreading 1/2 cup of frosting between each layer. Place the red layer upside down on top.

12. Apply a thin crumb coat of frosting over the entire cake and chill in the freezer for 10 to 15 minutes.

13. Apply the final thick layer of frosting and smooth the sides and top.

14. Decorate with rainbow sprinkles along the bottom border and pipe buttercream rosettes along the top edge. Add sprinkles to the rosettes.

15. Chill in the freezer for 20 to 30 minutes before slicing with a hot sharp knife.

Notes

Use room temperature butter and eggs for the best texture.

Gel food coloring is strongly recommended over liquid coloring.

Use a kitchen scale to portion the batter evenly into each bowl.

Do not skip the crumb coat step for a clean professional finish.

Store leftovers wrapped in plastic wrap in the freezer for up to 1 month.