Need some happiness in the form of a Rainbow Layer Cake? I think yes! Made with six colorful layers and a buttercream icing. The perfect birthday cake or cake for St. Patrick’s Day.
BIRTHDAY CAKE
My daughter just recently celebrated her 5th birthday. As I was looking for cake ideas I came across this idea for making a rainbow cake and of course my daughter and I both loved it. Who wouldn’t want a Rainbow Layer Cake for her birthday?
HOW TO MAKE A LAYER CAKE
INGREDIENTS
- 2 boxes of White Cake Mix
- food coloring
Directions:
I took two white cake mixes and mixed them up in a large bowl according to the directions on the box. Then I divided the batter into 6 different bowls. Each bowl ended up with about 1 and 3/4 cups of batter each. Then I mixed some food coloring into each bowl to get my rainbow colors. I used the gel food colors rather than the liquid drops.

Rainbow Layer Cake
Need some happiness in the form of a Rainbow Layer Cake? I think yes! Made with six colorful layers and a buttercream icing. The perfect celebration birthday cake.
Ingredients
- 2 boxes White Cake Mix
- 1-2 drops food coloring
Instructions
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I took two white cake mixes and mixed them up in a large bowl according to the directions on the box.
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Divide the batter into 6 different bowls. Each bowl ended up with about 1 and 3/4 cups of batter each.
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Mix some food coloring into each bowl to get my rainbow colors. I used the gel food colors rather than the liquid drops.
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When each color is mixed, place batter into 6 separate round 9 inch pans. I only had three, so I baked 3 first and then when they had cooled, I transferred the cakes to a cookie sheet. I washed the pans and baked the other 3 cakes. Be sure to grease your pans well so that the cakes come out without sticking. I baked the cakes in a 350 degree oven for about 12 minutes.
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After all the cake layers have cooled, place your bottom layer (purple) onto your cake plate. Add a thin layer of frosting. Place your blue cake layer on top of the frosting. Continue in this manner until you have added all your cake layers.
When each color is mixed, place batter into 6 separate round 9 inch pans. I only had three, so I baked 3 first and then when they had cooled, I transferred the cakes to a cookie sheet. I washed the pans and baked the other 3 cakes. Be sure to grease your pans well so that the cakes come out without sticking. I baked the cakes in a 350 degree oven for about 12 minutes.
After all the cake layers have cooled, place your bottom layer (purple) onto your cake plate. Add a thin layer of frosting. Place your blue cake layer on top of the frosting. Continue in this manner until you have added all your cake layers.
I have learned the trick for getting a nice clean frosting layer without all the cake crumbs in it. Have you ever had that problem? After you have your cake layers placed together, before you frost the rest of the cake, place your entire cake into the freezer for about an hour or so. Then take your frosting and lightly frost the entire cake.
LAYER CAKE
This layer will have a lot of crumbs in it, but don’t worry, they will not show. I forgot to take a picture of this step, sorry. Place your cake back into the freezer for another hour. This will seal your cake crumbs so that they will not stick to your final frosting layer. Take your cake out and frost the entire cake.
VANILLA FROSTING
This makes a very light and creamy frosting. This is just enough for frosting this BIG cake. Make sure to go easy on the frosting between layers so you have enough to cover the entire cake.
Right after I have frosted the entire cake, I take my flat spatula and dip it into a tall cup of hot water. Then with it clean of frosting, I run it over the frosting layer to give it a smooth finish. I continue washing the spatula in the hot water over and over until I like the results.



Light and Fluffy Vanilla Frosting Recipe
Ingredients
- 2 sticks salted butter room temperature
- 1 tsp vanilla 3-4 cups powdered sugar for a good consistency
- 1 Tbsp Milk
- 8 oz tub of Cool Whip
Instructions
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Place 2 sticks of salted butter, at room temperature (otherwise you will get chunks of butter in your frosting), into mixer and whip together until nice and smooth. Then add 1 teaspoon of vanilla. Gradually add about ½ to ¾ of a bag (regular size about 3-4 cups) of powdered sugar (Confectioner’s sugar). It will be a bit chunky and not very smooth. Gradually add 1 Tablespoon of milk while mixing frosting. If it is still not the consistency you desire, add another teaspoon of milk until you get a nice thick frosting that is smooth. Then fold in 1 tub of Cool Whip. That’s it.
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Then add 1 teaspoon of vanilla. Gradually add about ½ to ¾ of a bag (regular size about 3-4 cups) of powdered sugar (Confectioner’s sugar). It will be a bit chunky and not very smooth.
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Gradually add 1 Tablespoon of milk while mixing frosting. If it is still not the consistency you desire, add another teaspoon of milk until you get a nice thick frosting that is smooth.
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Then fold in 1 tub of Cool Whip. That’s it.
My family was so surprised at the colorful cake awaiting them when we cut into it. The cake is so colorful it makes me happy just to look at it. Imagine how you feel when you are actually eating it. This cake would be fun to make for all sorts of holidays or celebrations too!
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Hi there, I just wanted to say that I love the rainbow cake. Is the white cake mix really white? I'm not sure if I can get those here in Aus. Any suggestions?
that is super cake, love it, its huge, good job and happy b-day
Happy birthday for your little girl! That cake looks wonderful. I think especially children will love it. Great idea!
..i love cake..yummy!the bright colors do make it extra special.
in regards to your 3 column blog issue: i just made my blog 3 columns too…i blogged about it, where i got the "how to" tutorial etc.
rather than go into all that here…check it out on my blog…you might find some of the info. helpful.
~ move a gadget to your left column..should center your posts…leaving 1 narrower column on each side.
Do you have a link to your blog? Thinking about making myself this cake for my birthday in a few days
That cake looks teriffic! I just might have to consider making that. Thanks for the idea. :)
I love this idea! So colorful and fun. Reminds me of the Roy G. Biv thing from school to remember the colors of the spectrum.
Wow, Iove this idea! Thanks for all the details on how to make it!
That has to be the most beautiful cake I have ever seen.
i love this cake! what a great idea!! awesome work! & the pictures are beautiful!
My daughter turns 3 in a couple of weeks and I planned on making a rainbow cake. This idea is way better then the other one I found. Thanks so much, I will attempt this colossal layered cake :)
Happy Birthday to your daughter!
That cake is beautiful. I have seen other bloggers blog a rainbow cake recipe with just two layers with colors that fan out…I know confusing. I like yours the best.
So FREAKIN' cool!
Love the idea!!!!!! So fun! Maybe it is the perfect cake to make on a day even you are sad or your kids are having a bad day. I sure think that cake could cheer anyone up! :) I "heart" your blog! You really share the best ideas.
Cute! We decorated a plain sheet cake with rainbow jelly beans once. We made a marshmallow crown and then used those gold foil "coins" for the gold at the other end of the rainbow. I really like your layers though. Maybe we'll have to make another rainbow cake!
That's supposed to say marshmallow CLOUD not crown. sorry!
Blanche–If you can not find a white cake mix, you can just make a white cake from scratch. There are several recipes on the internet.
As far as it being a real "white" white cake…are you referring to the truly white ones made with just egg whites so the yolk doesn't tint the batter yellow? I used regular whole eggs and the batter was still white enough that adding the food coloring still produced the bright colors. Hope that helps.
I made this cake for my daughters birthday – it was a big hit.
I love this and am going to do it tomorrow!
Wow, this is awesome!
This is so darling- I showed my little girl who will be 5 in a month, and this is the cake she wants!!!
Wow!!!
My daughter and I love this cake! You must be the coolest mom! I've written a little something about you on my blog telling about your wonderful fun. http://ohitssewcute.blogspot.com/2009/07/idea-room.html
your photography is fantastic and really shows how CUTE CUTE this cake is…love the colored layers…
Great idea!!
HOPE~
I love it, the boys are begging me to make it for them.
I LOVE this idea!! Also for red, white and blue and other holidays. Great idea
Great idea!!! I'm trying to have a "cake file" on my computer because you don't know when you might need one. And when birthdays arrive your head seems not to think at the moment, have been there??? I LOVE IT!! My birthday is next month, and I may be even bake it for myself :)
Um, you just totally rocked that idea!! You are definately the "cool" mom on the block!!
Wow, what a huge cake and so fun and colorful!
gorgeous cake!! I will make one for my daughter birthday in sept and she will be 4 yrs old! thank you so much!!!
This cake makes my heart happy! I can't wait to show it to my girls and give it a try!
I ABSOLUTELEY LOVE this cake!!! So beautiful :D
I am not a fan of really sugary frostings and try not to use the frosting in a can. Can you tell me what you used??? (Even if it was frosting in a can! {he he!!})
Fantastic Cake…I think I will have to do this for my daughter's 3rd birthday this year…too cute!
Thank you for posting this and the great idea regarding frosting without the crumbs, which always happens to me!
Happy Birthday to you daughter!!