Easy Rainbow Cake {With Cake Mix}

Name: Easy Rainbow Cake (With Cake Mix)
Prep time: 10 min
Cook time: 30 min
Total time: 60 min
Ingredients: 3 Eggs (Large); 1/3 cup Butter (Unsalted, Melted); 1/2 cup Milk (Whole or 2%); 1/2 cup Water; 1 box White cake mix (Or yellow cake mix); Food coloring (Red, orange, yellow, green, blue, purple); 4 cups Whipped cream (Or Cool Whip); 1/4 cup M&m candies (Mini size); 2 tbsp Rainbow sprinkles

posted March 1, 2021 by CakeWhiz — This post may contain affiliate links. Please read my disclosure policy.

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Easy rainbow cake recipe, homemade with simple ingredients. Starts off with cake mix! Soft and moist cake layers are filled with whipped cream and topped off with sprinkles and colorful candies.

This cake will definitely hit the sweet spot. Not only does it taste amazing, it also looks fantastic plus it’s very simple to make, even for beginners. It’s perfect for kids birthday parties or even St.Patrick’s Day.

For more inspiration, be sure to check out this collection of Rainbow Desserts, Recipes, Ideas. Also, if you have a birthday coming up in your family and you are planning on making a special cake, you should definitely check out this huge list of Best Birthday Cake Ideas.

Rainbow Layer Cake on White Plate with Turquoise Background

How to make rainbow cake recipe (rainbow swirl cake)?

Prepare cake batter– By mixing together eggs, butter, milk, water, cake mix.
Divide batter– Into 6 separate bowls.
Color batter– Use a different color in each bowl.
Fill pans–They should be lined with parchment paper and greased.
Bake– Until an inserted toothpick in the center comes out clean.
Cool– Until they are room temperature.
Assemble– Place one cake on serving dish, top with whipped cream, place other cake on top, spread more whipped cream on top.
Enjoy– Toss some colorful candies and sprinkles on top and dig in.

Easy Homemade Rainbow Cake Slice on White Plate With Turquoise Background

How to make rainbow cake frosting?

Divide the prepared buttercream or whipped cream into six small bowls.
Add a different color in each bowl.
Then, take a sheet of saran wrap and spread each colored frosting in a straight line next to each other.
Next, roll the saran wrap.
Place it into a piping bag with a large star tip (Tip 1M) and it’s ready to use.

I used white whipped cream and did not do this because the cake was already so vibrant. However, this would work very well on chocolate cakes.

Closeup Shot of the Inside of Rainbow Birthday Cake With Slice Removed

Variations for Rainbow Birthday Cake

Pastel rainbow cake- Use lighter pastel food coloring instead of regular food coloring. They are readily available during Easter at most grocery stores but you can find them online too.

Chocolate rainbow cake- Make this Triple Chocolate Cake instead of the cake in the recipe card below. Once they cool, decorate in rainbow colored frosting instead of white frosting.

Ice cream cake- Follow the instructions in this post on How to Make Ice Cream Cake and make sure the ice cream layer is rainbow colored and then, frost the entire cake in rainbow colored frosting.

Pinata cake- Follow the instructions in this post on How to Make Pinata Cake and fill cake with sprinkles and small candies for a fun surprise.

Add more cake layers- I only have 2 layers but you can make it as tall as you like. 3 layer cakes are very popular. Simply make more batter and bake more cakes and stack them. Use dowels for support so that the cake doesn’t fall over, if you are making it very tall.

Fill them- Instead of using whipped cream as a filling, try jams and preserves or thick caramel sauce or even Nutella or peanut butter.

Try different frosting– Such as White Chocolate Buttercream Frosting or Marshmallow Frosting.

Overhead Shot of Sliced Layer Cake with Whipped Cream, Sprinkles, Candies

Tips and Techniques for rainbow layer cake

How to color batter? Use liquid food coloring or gel food colors.

Gel colors vs. Liquid food coloring– Either can be used. Gel food coloring is more concentrated than liquid food coloring. It gives a more vibrant color and you don’t need to use a large quantity.

Do not decorate or assemble warm cake- Because this will cause the frosting to melt and create a sticky mess. Let the cakes cool completely.

Can you freeze cake with icing? No. Whipped cream is made with dairy and does not thaw well. You can freeze unfrosted cakes and then ice them upon thawing.

Cake mix vs. Scratch recipe– Using cake mix is easy and convenient but a scratch recipe can be used too. Try this Best Vanilla Cake Recipe (From Scratch). Divide the batter and color it and then, bake.

Why did my cake turn brown on top? It has been baked for too long. When cakes are over-baked, the tops become brown and hard. They also become dry on the inside.

How to know cakes are done baking? Insert a toothpick in the center and if it comes out clean, they are ready to be removed from the oven.

Line pans with parchment paper and grease the sides- This is very important because it prevents the cakes from sticking to the pans and thus, making it easier to remove them from pans.

Unfrosted Freshly Baked Rainbow Swirl Cake in Silver Pan on White Background

Another cake design

Another approach to this rainbow design is to use Twizzlers. Use them to decorate the outside of the cake instead of keeping it exposed.

Use scissors to cut Twizzlers. The length of these Twizzlers should be the same as the height of your cake.
Fill, frost and stack the two cakes in buttercream icing.
Stick the Twizzler pieces around the cake. The icing works like glue.
Place some colorful Rolo candies on top of the cake and toss some silver edible pearls to fill any gaps.

This is very similar to my yellow and black Halloween Cake and the super popular red and green Christmas Cake.

Colorful Candy Cake on Stack on Plates With Black Background

More Rainbow Desserts

Storage

Refrigerate- Store leftovers in a sealed container for up to 3 days.

Freeze- Unfrosted cakes can be frozen in a sealed container for up to 1 month. When you are ready to enjoy it, thaw cakes in fridge overnight and then assemble with frosting.

Make ahead instructions- This cake can be baked and decorated 1 day in advance and stored in the fridge until you are ready to serve.

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