Easy Rainbow Cake

The sweetest mini celebration cake! Five layers of colorful, moist cake with vanilla frosting and a confetti of rainbow sprinkles. Simple and suitable for small crowds, this little layer cake is delicious and fun for all ages!

After celebrating my daughter’s sixth birthday with this gorgeous (and easy) sprinkled rainbow cake, we decided we must share it with you! The vibrant colors and fluffy, moist layers of frosted cake were so warmly received by our small crowd. Everyone at the festivites, from young to old, was happily surprised when a beautiful rainbow was revealed after the first slice!

Novice bakers, trust me: This cake is easier to make than it may first appear. I am no professional baker, but was determined to pull of a pretty and delicious homemade cake for our celebration. Didn’t care if it had that “homemade” look, or tilted to one side – adds to the charm, right?

For this recipe, I used smaller 6-inch pans to make it mini, but with five layers, this cake still feeds a gathering of 8-10 people. You can spread the same batter into 8-inch pans for thinner layers and a slightly wider cake. This will serve closer to 12-14 people.

This ridiculously fun rainbow cake is sure to impress your party guests! Easy to make with semi-homemade ingredients and melt-in-your-mouth flavor. Everyone loves a sprinkled party cake for a creative and fun twist on traditional desserts!

Easy Rainbow Cake

Easy Rainbow Cake

Yield: 8 servings


For rainbow cake layers:

  • Nonstick cooking spray
  • 2 (16.25 oz.) boxes white cake mix
  • 2 cups water
  • 1 cup vegetable oil
  • 6 large eggs
  • Gel food coloring (red, yellow, green, blue)

For decorating:

  • 2 containers (about 3 cups) white or vanilla frosting
  • about 2 cups rainbow sprinkles


For rainbow cake layers:

  1. Preheat oven to 350 degrees F. Spray round cake pans with nonstick cooking spray.
  2. In large bowl, combine cake mix, water, oil and eggs. Beat with electric mixer on low speed for 30 seconds, then on medium speed for 2 minutes, scraping bowl occasionally. Divide batter evenly among 5 bowls, about 1-1/3 cups each.
  3. Using food colors, tint batter in separate bowls red, orange (using red and yellow), yellow, green and blue. Start with a small amount of coloring, and adjust as needed.
  4. Pour each colored batter into separate cake pans (use one at a time if you don't have 5 pans). Set aside and cover remaining batter until ready to use.
  5. Bake 25 to 30 minutes (depending on size of your cake pan), or until cake springs back when touched lightly in center and begins to pull away from side of pan. Cool 10 minutes. Remove from pans to cooling racks. Cool completely before frosting.
  6. Once cake has cooled completely, slice domed top with a sharp knife to flatten. This will help you layer the cakes evenly.

For decorating:

  1. With a flat spatula, evenly spread a thin layer of white frosting on your bottom cake layer. Top with remaining layers, spreading frosting between each.
  2. Spread a thin layer of frosting all over the entire cake. This is your "crumb coat" (one of two frosting layers) that holds everything together. Refrigerate until firm, at least 1 hour.
  3. Spread with remaining frosting. Coat all over with rainbow sprinkles. Refrigerate until firm and ready to serve.

Special Equipment Needed

  1. Electric mixer
  2. 5 medium bowls
  3. 6-inch or 8-inch round cake pans
  4. Icing spatula or flat spatula

Did you make this recipe?

Please leave a comment on the blog or share a photo on Pinterest

Join the Conversation

  1. This looks so good! How did you get sprinkles on the edges? How do they stick?

  2. Thank you, Colleen. I put the sprinkles in a bowl and patted the top and edges of the cake with the sprinkles. Kind of like this video shows: https://www.youtube.com/watch?v=exCv946aKBw

  3. 5 stars
    Rainbow cake wow it is really very delicious and also something that kids would love. I am going to try this out for my daughter’s birthday and I know it will turn out to be very well. Thank you so much for putting this up.

  4. Hi, I’m wondering if I can use a frosting that’s not as sweet. Maybe with a bit of whipped cream mixed in it. It would make it not so firm but do u think it will hold up between layers?

  5. Hi Bea, I would not recommend mixing the frosting with whipped cream.

  6. 5 stars
    Thank you for this! It was a huge hit at my 4 yo’s birthday party ♥️ Not too difficult to make, either!

  7. Beautiful cake! Do you know where you bought those sprinkles? All the ones I see have have purple and other colours that won’t match the layers inside. Thanks!

  8. Thank you, Allie! I got the rainbow cake sprinkles from my local grocery store.

  9. Monika Bardos says:

    5 stars
    Hi! How tall was each layer in your cake?
    My 6 inch pans are just 1 inch tall. I just wondering if I still need 2 box of cake mix or just one?
    It looks absolutely delicious and cute. Can’t wait to make it to my little one.

  10. Hi Monika! I trimmed about a half-inch worth of “dome” on each cake layer with a bread knife, once it was baked and cooled. So, this resulted in layers about 1-1/2 inches high. You definitely need two boxes in order to be able to create all the colors, if you’re going for a rainbow effect. I hope that helps!

  11. Monika Bardos says:

    5 stars
    Thank you very much your answer. I appreciate your help.

  12. 5 stars
    OMG!!!!!! This cake looks SUPER moist and delicious!!!
    Can not wait to try this recipe out and make this cake for Pride Month this June!!!!!
    Girl…….. you know how to bake!!!!!!:)

  13. Wow, thanks Alex! Such a great idea to bake this for Pride Month!

  14. 5 stars
    This looks great, I’m going to cut a hole in the middle and fill it with sprinkles and/or mini M&M’s

  15. Mariyam Raisha Riffath says:

    5 stars
    Wow I really loved this. I am 11 years old and I loved baking lots of types of cake. And by reading this, it gave me a lot of ideas, I think I should also try this too to make this rainbow cake at my 12th birthday…!!

  16. 5 stars
    Wow I really loved this I am 11 yrs old, and I love baking lots of types of cake. And by reading this, it gave me lots of ideas, I think I should also try this too to make this rainbow cake at my 12th birthday…!!

  17. Lauren Stachura says:

    What kind of frosting? Can I make my own, or will the consistency be off?

  18. Any store-bought container frosting, or equivalent amount of homemade frosting, works fine.

  19. It looks so beautiful!! Thanks for sharing this.

  20. Jessica Lepri says:

    I was wondering how many boxes you would use for a sheet cake? We have a bigger kid party coming up, so I was going to try and make it a rectangle.

  21. I’m really not sure, sorry! Adding more boxes of cake mix would change the other ingredients, and I haven’t tried this before, so couldn’t vouch for its success.

  22. How much frosting did you use to spread in between the layers? Thank you. beautiful cake.

  23. I don’t know exactly, maybe 2 cups total (about 1/3 cup each layer).

  24. Thank you for this colorful cake! I’ve included it in my roundup of fun rainbow desserts! Thanks again!

  25. Thank you for letting me know, and for your kind words, Chelsea. I appreciate you!

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