This Rainbow Cake is a colorful layered cake recipe that is perfect for birthdays, parties, St. Patrick’s Day, and special celebrations. Made with vibrant rainbow cake layers and creamy homemade buttercream frosting, this easy cake recipe looks impressive but is simple to make.
We love making this rainbow birthday cake for kids because the bright colors make every celebration extra memorable and the recipe can easily be made ahead for parties.
Why You’ll Love This Recipe!
We love making this Rainbow Cake for birthdays because it always surprises everyone when sliced. Even though it looks fancy, the recipe uses simple ingredients and boxed cake mix to keep things easy and stress-free for busy families.
- Bright colorful layers inside every slice
- Perfect for birthdays and parties
- Kid-friendly baking project
- Can be made ahead of time
- Easy to customize with frosting and sprinkles
No matter the occasion, this cake always makes a great centerpiece dessert for your celebration!
Ingredients
- White Cake Mix – White cake mix creates bright rainbow colors because the batter stays light. Vanilla cake mix also works but may slightly affect the colors.
- Rainbow Colors of Gel Food Coloring – Gel food coloring gives the cake vibrant colors without thinning the batter. A little goes a long way compared to liquid food coloring.
- Butter – Use softened butter for smooth and creamy buttercream frosting.
- Clear Vanilla Extract – Clear vanilla helps keep the frosting bright white for a cleaner rainbow look.
- Confectioners Sugar – Sift the powdered sugar before mixing to help create fluffy frosting without lumps.
How to Make a Rainbow Cake
Step 1 – Heat Oven – Preheat the oven to 350 degrees Fahrenheit. Then spray 3 (8-inch) round cake pans with a non-stick cooking spray.
Step 2 – Combine Cake Ingredients – In a large bowl, beat with a hand held electric mixer or a stand mixer. We use the paddle attachment. Combine the cake mixes, water, oil and eggs until the mixture is smooth and creamy.
Step 3 – Divide Cake Batter – Then divide batter evenly into 6 small bowls. There should be approximately 1 ½ cups of batter in each bowl. Use the gel food coloring to dye each bowl of icing a different color of the rainbow. I used red, orange, yellow, green, blue and purple.
Step 4 – Place in Fridge – Refrigerate 3 colors of the batter. Pour the remaining 3 colors each into a separate baking pan.
Step 5 – Bake Cake – Bake for 18-20 minutes until a toothpick inserted into the middle of the cake comes out clean.
Step 6 – Cool Cakes – Let the cakes cool for 10 minutes. Then carefully remove from the pans. Allow them to cool completely to room temperature on wire racks.
Step 7 – Wash Pans – Wash the cake pans. Re-spray for non-stick cooking spray. Then pour the remaining colors of the batters into the pans. Bake the same as you baked the 1st 3 colors. Let them cool completely on wire rack.
Step 1 – Cream Butter – In a large bowl cream the butter until smooth.
Step 2 – Add in Powdered Sugar – Beat in the confectioners sugar (one cup at a time). Beat on low speed until well combined.
Step 3 – Add Milk – Stir in vanilla and milk. Whip until thoroughly mixed and fluffy on a medium-high setting.
How To Assemble
Step 1 – Trim Cake Tops – Use a serrated knife to trim the cake layers. This make sure that both of the cakes are leveled.
Step 2 – Purple Layer – Place the purple cake on a large cake plate or cake stand.
Step 3 – Layer with Frosting – Spread a thin layer of frosting on top of this purple cake layer.
Step 2 – Add Other Cake Layers – Repeat this process with the blue, green, yellow, orange layer and red cakes.
Step 3 – Add Frosting – Then frosting the sides of the cake and decorate the top as desired with the rainbow sprinkles.
Step 4 – Serve – Then the rainbow layer cake is ready to slice, serve and enjoy.
Tips for Success
- Removing Cake Tops – Before frosting the cake layers, make sure to smooth the top with a knife. This helps the cake to be even and prevents it from falling.
- Prepare Cake Pans – Before pouring the cake batter into the pans, make sure to grease with cooking spray. This prevents the cakes from sticking and to easily remove from pan. It also helps to make sure cake has cooled before removing.
- Combining Cake Ingredients – We recommend using a electric mixture or a stand mixer to combine cake ingredients. Beat the cake mix ingredients on medium speed. This ensures that the cake batter is smooth and creamy.
- Dividing Batter – Feel free to make this cake in as many layers as you prefer. We did 6 layers but you can easily do less. You will have to work in batches depending on how many round cake pans you have. Just make sure to divide the batter evenly to ensure that the cakes are even when stacking.
- Adding the Food Coloring – When making this rainbow cake it is all about the vibrant shades of color. Make sure to use quality food coloring to dye the cake with. Add as much food coloring as your prefer. Add more to make it more vibrant colors.
- Frosting the Cake – We recommend preparing the cakes ahead of time to ensure they are completely cooled before frosting. We like to place on cooling racks to cool. Frosting the cake creates a crumb coat.
- Butter – The butter is best when it is softened. When combining the unsalted butter with the other ingredients it provides a smooth and creamy texture.
Variation and Substitutions
- Frosting – We used a homemade butter cream frosting. You can also make this cake with a cream cheese frosting if you prefer. Feel free to use store bought frosting.
- Cakes – To make this cake recipe easy, we used box cake mixes. But feel free to make homemade cakes with baking powder, baking soda, and all purpose flour.
- Cake Flavor – We used a white cake mix in this recipe. But you can use a vanilla cake if you prefer. It may alter the colors on the cake but it will still taste amazing.
- Decorating Cake – Feel free to decorate the cake how you prefer. You can even use a piping bag to pipe designs on the cake.
Storage and Freezing Tips
Refrigerate the leftover cake and cover with plastic wrap. Store the cake for up to 5 days.
To freeze:
- Freeze unfrosted cake layers individually wrapped
- Store for up to 3 months
- Thaw overnight in the refrigerator before assembling and frosting
This is a great make-ahead cake for birthday parties and celebrations.
Frequently Asked Questions
In this recipe we used 3 cake pans. Depending on how many cake pans you have, you may need to work in batches. Just make sure to wash and spray with cooking spray after baking the cakes.
To prevent the cake from leaning, make sure to level the cake toppings. You also want to make sure to pour the exact amount of cake batter into each cake pans.
Gel food coloring works best because it creates bright colors without changing the batter texture.
Yes, homemade white cake batter works great if preferred.
More Easy Dessert Recipes
This Rainbow Cake is one of our favorite celebration cakes because it is colorful, fun, and always surprises everyone when sliced. It is perfect for birthdays, parties, and special occasions.
If you make this recipe, leave a comment and star rating below. We love hearing how your family celebrated with this fun rainbow cake.
Rainbow Cake Recipe
Ingredients
For the Cake:
- 2 boxes White Cake Mix
- 2 cups Water
- 1 cup Vegetable Oil
- 6 large eggs
- Rainbow Colors of Gel Food Coloring
For the Frosting:
- 2 cups Butter softened
- 2 tsp Clear Vanilla Extract
- 8 cups sifted Confectioners Sugar
- 4 Tbsp Milk
- Rainbow Sprinkles optional
See how we calculate recipe costs.
Instructions
For the Cake:
- Preheat the oven to 350 degrees Fahrenheit and spray 3 (8 inch) round cake pans with a non-stick cooking spray.
- Prepare 2 boxes white cake mix with 2 cups water, 1 cup vegetable oil, and 6 large eggs according to the package directions.
- Then divide the batter evenly into 6 small bowls (should be approximately 1 ½ cups of batter in each bowl). Use the gel food coloring to dye each bowl of icing a different color of the rainbow. I used red, orange, yellow, green, blue and purple.
- Refrigerate 3 colors of the batter and pour the remaining 3 colors each into a separate baking pan.
- Bake for 18-20 minutes until a toothpick inserted into the middle of the cake comes out clean.
- Let the cakes cool for 10 minutes and then carefully remove from the pans and allow them to cool completely on wire racks.
- Wash the cake pans. Re-spray for non-stick cooking spray and pour the remaining colors of the batters into the pans. Bake the same as you baked the 1st 3 colors. Let them cool completely.
For the Frosting:
- In a large mixing bowl, beat 2 cups softened butter until smooth.
- Beat in the confectioners sugar (one cup at a time) on low speed until well combined.
- Stir in vanilla and milk. Whip until thoroughly mixed and fluffy on a medium-high setting.
To Assemble:
- Use a serrated knife to trim the cake layers to make sure that both of the cakes are leveled.
- Place the purple cake on a large plate or cake stand.
- Spread a layer of the frosting on top of this cake.
- Repeat this process with the blue, green, yellow, orange and red cakes.
- Then frosting the sides of the cake and decorate the top as desired with the rainbow sprinkles.
- Then the cake is ready to slice, serve and enjoy!
