Rainbow Cake has 6 colorful layers stacked between luscious buttercream frosting. This gorgeous cake is a showstopper, and it tastes amazing too.

Slice of rainbow cake on a plate.
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Rainbow Cake

Once you slice into this Rainbow Layer Cake, you will see all the stunning layers. With 6 colorful layers, it is such a pretty cake recipe. This cake would be perfect for a rainbow themed birthday party, St. Patrick’s Day or any special occasion.

The recipe starts with a cake mix so it is very easy to make. The frosting is homemade buttercream and this white frosting is rich and delicious. Top the cake with rainbow sprinkles if desired for an extra special touch! Another fun and colorful treat is Easy Rainbow Sugar Cookies.

We love to make cakes and also enjoy Hummingbird Cake, Margarita Cake, Mardi Gras King Cake Recipe, Honey Bun Cake Recipe and Easy Homemade Zucchini Cake Recipe.

Ingredients for Rainbow Cake.

Ingredients: 

Cake: 

  • White Cake Mix
  • Water
  • Vegetable Oil
  • Large eggs
  • Rainbow Colors of Gel Food Coloring

Frosting: 

  • Butter (softened) 
  • Clear Vanilla Extract
  • Confectioners Sugar
  • Milk
  • Rainbow Sprinkles (optional) 

How to make Rainbow Cake:

  • Step 1. Preheat the oven and prepare the cake pans. Preheat the oven to 350 degrees Fahrenheit and spray 3 (8 inch) round cake pans with a non-stick cooking spray.  
  • Step 2. Combine the cake ingredients. In a large bowl, beat with a hand held mixer or a stand up mixer. Use medium speed to combine the cake mixes, water, oil and eggs until the mixture is smooth and creamy.
  • Step 3. Divide the cake batter. 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.
  • Step 4. Chill a portion of the batter. Refrigerate 3 colors of the batter and pour the remaining 3 colors each into a separate baking pan.  
  • Step 5. Bake the cake. Bake for 18-20 minutes until a toothpick inserted into the middle of the cake comes out clean. 

    Make sure the pans are all the same brand and size. Otherwise, they bake differently as the size is different.
  • Step 6. Allow to cool and remove from the pan. Let the cakes cool for 10 minutes. Then carefully remove from the pans and allow them to cool completely on cooling racks.  
  • Step 7. Wash the cake pans and reuse.   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.  

How to make the frosting:

  • Step 1. Cream the butter. In a large bowl cream the butter until smooth.
  • Step 2. Gradually add the powdered sugar. Beat in the confectioners sugar (one cup at a time) on low speed until well combined.
  • Step 3. Stir in the vanilla and milk.  Whip until thoroughly mixed and fluffy on a medium-high setting.

Assemble the cake:

  • Step 1. Trim the layers until they are level. Use a serrated knife to trim the cake layers. Make sure that both of the cakes are level.
  • Step 2. Start adding frosting. Place the purple cake on a large plate or cake stand.
  • Step 3. Add a layer of frosting. Spread a layer of the frosting on top of this cake.
  • Step 4. Continue with all the layers. Repeat this process with the blue, green, yellow, orange and red cakes.  
  • Step 5. Add remaining frosting. Frost the sides of the cake with a crumb coat and then add remaining frosting. Decorate the top as desired with the rainbow sprinkles.  
  • Step 6. Serve and enjoy this cake. Then the cake is ready to slice, serve and enjoy! 

Storage:

Refrigerate the leftover cake, covered, for up to 5 days. 

Tips for the Best Cake:

  • Make the layers level. If your cake is domed shaped once you bake it, level the cake with a serrated knife. This will help the layers to stack evenly.
  • Allow the layers to cool. The layers need to cool completely before adding frosting or it will slide off.
  • Room temperature butter. The frosting will combine smoother if the butter is room temperature.
  • Don’t overmix the cake batter. Combine the cake ingredients until just combined. Mixing the ingredients excessively will make the cake dense instead of soft and fluffy.
  • Allow to cool before removing from pan. The cake needs to cool slightly before removing from the pan. This will help it to come out easier and not fall apart.
  • Adjusting the colors of the cake. You can add as much or as little food coloring as you prefer. The colors can be as vibrant or as faint as you desire.
  • Remove any excess frosting. As you frost the layers, remove the excess frosting so you have a clean edge when you frost the outside.
  • Divide the batter evenly. Make sure that you divide the batter evenly between all of the cake pans. You do not want varying sizes of cake layers.

Variations

  • Store bought frosting. If you want to save more time, use store bought frosting instead of homemade in this recipe.
  • Different colors of layers. You can make this any color you want. It would be fun to do red and green at Christmas, different shades of purple for someone’s favorite color and more. The ideas are endless for this rainbow layer cake.
  • Different colors of frosting. We used white but you can use any color you prefer in this recipe.
Rainbow Cake being sliced.

Can I make this cake in advance?

Yes, you can make the cake layers in advance. However, it is best to assemble the cake when ready to serve. Make each cake layer up to 2 to 3 days in advance.

Wrap each layer securely in plastic wrap and store in the refrigerator. Add the icing to the layers and assemble the cake when ready to serve. See How Long Does Cake Last in the Fridge.

Rainbow cake ready to be sliced.

Can I freeze this cake?

You can freeze the unfrosted cake layers up to 3 months. Wrap in plastic wrap and foil.

Place in the freezer. Make sure it is completely cool before freezing. Allow to thaw in the refrigerator overnight when ready to use. Then decorate as normal.

Another option is to freeze the cake completely frosted and decorated. If you have leftovers, freeze the slices up to 3 months.

We prefer to flash freeze the slices on a baking sheet for 1 to 2 hours. Then wrap in plastic wrap and foil to freeze. The extra step of flash freezing will keep the icing intact and the cake will still look great.

Rainbow Cake being sliced.

Frequently Asked Questions

What if I only have 3 pans?

If you only have 3 pans, make the cakes in batches. Bake the 3 cake layers first. Then wash the pans and reuse the same pans.

How do I prevent my cake from leaning?

Use cake pans that are all the same brand and size. You do not want to use various brands.

They may not be the same size and the layers will be uneven. This will cause the cake to lean.

What food coloring do you use for a vibrant cake?

Use gel food coloring for the prettiest most vibrant colors.

This beautiful cake is one of a kind. It looks so fancy and gorgeous. However, it is very easy to make.

Suprise your friends and family with this stunning dessert at your next party or function. Once you slice into it, the layers are gorgeous.

Slice of rainbow cake on a plate.

Print this Rainbow Cake Recipe below:

Rainbow Cake

5 from 2 votes
Rainbow Cake has 6 colorful layers stacked between luscious buttercream frosting. This gorgeous cake is a showstopper and it tastes amazing too.
Prep Time 30 minutes
Cook Time 20 minutes
Let Cool 10 minutes
Servings 12
Cuisine American
Course Dessert
Calories 1100

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
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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.
  • In a large bowl, beat with a hand held mixer or a stand up mixer the cake mixes, water, oil and eggs until the mixture is smooth and creamy.
  • 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 bowl cream the 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!

Recipe Notes

Refrigerate the leftover cake, covered, for up to 5 days.

Nutrition Facts

Calories 1100kcal, Carbohydrates 150g, Protein 7g, Fat 54g, Saturated Fat 25g, Polyunsaturated Fat 12g, Monounsaturated Fat 14g, Trans Fat 2g, Cholesterol 164mg, Sodium 877mg, Potassium 103mg, Fiber 1g, Sugar 115g, Vitamin A 1072IU, Calcium 218mg, Iron 2mg

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Slice of rainbow cake on a plate.

More Easy Cake Recipes:

Rainbow Cake has 6 colorful layers stacked between luscious buttercream frosting. This cake is a showstopper and it tastes amazing too. The recipe starts with a cake mix so it is very easy to make. The frosting is homemade buttercream and this white frosting is rich and delicious. Top the cake with rainbow sprinkles if desired for an extra special touch! #dessertsonadime #rainbowcake #rainbow

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About the Author

Hi, I’m Carrie. Welcome to Desserts on a Dime!

I’m on a mission to help you create delicious desserts on a budget and do not require a ton of time. Together, we are going to make something sweet that the entire family will love!

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