This rainbow cake just makes me feel so happy. I absolutely LOVED slicing into it to see all those gorgeous colorful layers! The best part is, this rainbow cake isn't just for looks, it tastes absolutely amazing. You won't have a crumb leftover.
This rainbow cake is very special to me. I've been waiting to make it for a long time. Ever since we found out we were pregnant with our son, Ezra, I knew I wanted to make him a rainbow cake for his half birthday (6 months).
Most people know that my husband and I had to go through a lot of infertility treatments to get our dear Avalon. I'm not ashamed of it. I think we should talk more about infertility and how common it is. So we feel less alone.
We started treatments TWO years ago. Nothing was working. My body was fighting against me. I was not in a good place emotionally or mentally.
It might sound crazy but I had a dream we had a son. I didn't tell anyone but I held onto hope as best I could.
We had honestly almost given up that we would ever have a second child. But I just felt in my soul that we had a second child waiting for us. So we didn't give up.
After all those treatments and all those medications, we ended up with ONE single egg. If you've gone through IVF you. know that the chances of that ONE egg taking are extremely low. I did not get my hopes up.
But that one egg did stick. And here we are with our beautiful baby boy. Our rainbow after the storm. Our lucky charm. The completion of our family.
What cake recipe is best for rainbow cake?
So the first thing that we have to do is bake our rainbow layers. This might sound intimidating but it's actually really easy.
We're going to use my favorite cake, white velvet. Not only. is this cake delicious, but it's also very white so it will take the color well.
If you try to add color to a vanilla cake that has egg yolks in it, those yolks will distort your colors while baking.
The other reason white velvet is perfect for making a rainbow cake is that it won't get over-mixed when you add the color.
I've added color to white velvet so many times, making everything from pink velvet, green velvet, and even blue velvet. The texture always turns out amazing.
How to make rainbow cake layers
Get your 8"x2" cake pans ready. You might not have 6 cake pans all the same size (I don't) so keep your cake batter in the fridge while your other cakes are baking. They are really thin so they bake up fast.
Coat your cake pan in a layer of cake goop and preheat your oven to 335ºF. I also put a piece of parchment paper in the bottom of my pans so that they were easier to take out of the pan since they would be so thin.
To make our rainbow cake layers, all you have to do is mix up your batter (follow the recipe below) and then divide your batter into 6 bowls evenly.
Each bowl holds 15 ounces of cake batter. I used a kitchen scale to weigh mine out so they would all be equal.
I'm using electric colors from Americolor and I'm not making an EXACT rainbow, this rainbow is more Lisa Frank style. I really like these electric colors because they make super bright neon colors and you don't have to use a lot of food color.
Colors I used
- Electric Purple
- Electric Blue
- Electric Green
- Electric Yellow
- Electric Orange
- Electric Pink
You can totally go classic rainbow and use red instead of pink, violet instead of electric purple and royal blue instead of electric blue.
Add a drop or two of color to each bowl and stir with a spoon until combined. Make sure for the green you use a little yellow and a little green so the green is more vibrant.
For the orange, use a little orange and a little yellow to make the orange more vibrant.
For the purple, add a little pink and purple to make the purple more vibrant.
Pour your batter into your cake pans (I baked three at a time and put 15 ounces of batter in each pan).
When they are done baking, they will start to pull a tiny bit from the edges of the pan (that's normal) let them cool a bit in the pan before turning out onto a cooling rack to fully cool down.
I put my cakes into the freezer for about 30 minutes to firm them up before trimming off the dome, the brown sides, and the brown bottom.
Trimming your cakes just makes the slices extra perfect and beautiful when you slice them.
How to decorate a rainbow cake
Time to decorate our rainbow cake! I'm using my easy buttercream because it comes together so fast. You could use any buttercream though like swiss meringue buttercream, Italian meringue buttercream or even cream cheese frosting.
Place your first layer onto your cake board. I'm working on a turntable to make this whole process easier.
Apply a thin layer of buttercream. Shoot for about ¼" of frosting.
Keep your spatula nice and flat so your buttercream has an even thickness.
I'm starting with the purple because that makes sense to me in my brain but you could start with the pink if you want to go in the opposite direction.
Continue frosting and stacking this way with the rest of the layers and then give the whole cake a nice crumb coat to seal in all those rainbow crumbs.
Chill your cake for 15 minutes to firm up that layer of buttercream.
Finish your cake with a final layer of buttercream and smooth it out with your bench scraper and offset spatula.
After chilling my cake, I added some fancy sprinkles to the bottom border of the cake, then I transferred my cake to a cake board.
I'm finishing this cake with a water ganache drip. I used 5 ounces of white candy melts, 1 ounce of chocolate candy melts and 6 ounces of water.
After melting, I added a few drops of electric yellow food coloring to make a gold candy melt color. I dripped this water ganache onto my chilled cake. Then painted gold with some truly mad plastics gold dust and vodka.
Make sure your mixture of dust and vodka is fairly thick, like paint so that you get good coverage.
Then I added some little swirls of white frosting on top and added some more sprinkles. I used a 1M piping tip to do the swirls.
And we're done with our rainbow cake! Doesn't it look so pretty! I love how the slices look and they are the perfect accent to this month's Ezra photo.
Be sure to check out my other popular cake recipes for more delicious tried and true cake recipes that never disappoint.
Cake Batter and Frosting Calculator
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Cups of Batter Needed
8 cups
Cups of Frosting Needed
5 cups
Note: measurements are estimated based off the vanilla cake recipe using standard US cake pans and sizes. Measurements used are for 2" tall cake pans only. Your results may vary. Do not overfill cake pans above manufacturer's recommended guidelines.
Recipe
Equipment
- Stand Mixer
- Whisk Attachment
- Paddle Attachment
- Turntable
- Piping Bag
- 1M Piping Tip
Ingredients
Rainbow Cake Ingredients
- 24 oz cake flour
- 24 oz granulated sugar
- 1 teaspoon salt
- 2 tablespoon baking powder
- 1 teaspoon baking soda
- 10 oz egg whites room temperature
- 6 oz vegetable oil
- 18 oz buttermilk room temperature or slightly warm
- 12 oz butter unsalted and softened
- 1 Tablespoon vanilla extract
Easy Buttercream Frosting Ingredients
- 8 oz pasteurized egg whites
- 32 oz powdered sugar
- 32 oz unsalted butter softened but not melted
- 2 teaspoon vanilla extract
- ½ teaspoon salt
- 1 dot purple food coloring to make the buttercream white
Gold Drip
- 5 oz white candy melts
- 1 oz chocolate candy melts
- 1 oz hot water
- 1 teaspoon Truly mad plastics super gold dust
- ¼ teaspoon everclear or vodka or lemon extract
Instructions
- NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and measured by weight so that the ingredients mix and incorporate correctly. Heat oven to 335º F/168º C
- Prepare six ( 8"x2") cake pans with cake goop and place a round piece of parchment paper in the bottom of the pan for easy removal of the cake
- Combine 8 oz of the buttermilk and the oil together and set aside.
- Combine the remaining buttermilk, egg whites, and vanilla together, whisk to break up the eggs and set aside.
- Combine flour, sugar, baking powder, baking soda and salt in the bowl of a stand mixer with the paddle attachment. Mix 10 seconds to combine.
- Add your softened butter to the dry ingredients and mix on low until mixture resembles coarse sand (about 30 seconds).
- Add in your milk/oil mixture and let mix until dry ingredients are moistened and then bump up to med (setting 4 on my KitchenAid) and let mix for 2 full minutes to develop the cake's structure. If you don't let your cake mix on this step your cake could collapse.
- Scrape your bowl and then reduce speed to low. Add in your egg white/milk mixture in three batches, letting the batter mix for 15 seconds between additions. Scrape down the sides again to make sure everything has incorporated.
- Divide your batter into 6 bowls. Weigh 15 ounces of batter for each bowl.
- Color each bowl with your Electric food colors. ½ teaspoon for pink for the pink layer, ¼ teaspoon yellow plus ¼ teaspoon orange for orange layer, ½ teaspoon yellow for yellow layer, ¼ teaspoon yellow plus ½ teaspoon green for green layer, ½ teaspoon blue for blue layer, ¼ teaspoon pink and ½ teaspoon purple for the purple layer.
- Bake your layers for 20-24 minutes or until the edges JUST start pulling away from the cake pan. Do not under-bake or the middle of the cake will collapse.
- IMMEDIATELY TAP PAN FIRMLY on countertop once to release the steam from the cake. This stops the cake from shrinking.
- Let cakes cool for 10 minutes inside the pan before flipping them out. The cake will shrink a bit and that is normal. Freeze your cake layers 30-60 minutes before trimming your cakes. Frost and fill with buttercream frosting.
- After your buttercream is smooth, place the cake back into the fridge for 15 minutes before you apply your drip.
- Wait for your drip to set before painting with gold paint. Finish the cake with buttercream rosettes and more sprinkles.
Easy Buttercream Instructions
- Place powdered sugar and pasteurized egg whites in the bowl of your stand mixer with the whisk attachment.
- Mix on low to combine then increase speed to high.
- Add the butter in small chunks while mixing. Continue mixing until all the butter is added in. Then add in your vanilla and salt.
- Mix on high until light and fluffy and no longer tastes like butter. Add a dot of purple food coloring to reduce the yellow appearance of the buttercream (optional).
- Remove the whisk attachment and replace it with the paddle attachment. Mix on low for 10 minutes to remove bubbles from the buttercream.
Gold Drip Instructions
- Melt the chocolate in the microwave in 15-second increments until almost fully melted.
- Add in your hot water and microwave another 15 seconds
- Stir until smooth. Then add in your yellow food coloring. Stir until smooth.
- Place water ganache into a piping bag, snip off the tip and drip the ganache around the edge of your chilled cake. After it sets, you can mix your gold dust and vodka together and paint the drip gold
Video
Notes
Cake flour sources: UK - Shipton Mills Cake & Pastry Flour
Shannon says
Can I use normal.egg whites for the butter cream icing?
Elizabeth Marek says
No you cant, you would have to use the Swiss Meringue Buttercream method for regular egg whites
Stephany says
ALL I CAN SAY IS AMAZING! I am not a professional baker AT ALL and braved this cake for my daughters 9th birthday! It came out amazing! I accidentally turned the buttercream a light pink bc I put too much purple but it came out great! And it is sooo good. Not too sweet and the buttercream is perfect! The best part was cutting into the cake and seeing my daughters face light up when she saw all the colors! Thank you for this recipe!
Kate says
Thanks so much for this recipe. I am hoping to try it today. I am a baking novice so excuse the silly question. I bought gold dust but don’t have the vodka extract. Can I mix the gold dust with wet icing sugar and get a similar result? I also bought old gold food colouring but no idea how this can be used. I would imagine it might give a yellow colour. Any advice appreciated!
Elizabeth Marek says
The dust needs to be mixed with something clear like lemon extract or clear vanilla extract if you don't have alcohol.
Anita C says
I want to make a 6" cake instead of 8". Can I still use all the same measurements or would the cake be too tall?
I'm okay with a taller cake but I feel like maybe six 1" layers is too much. What do you think?
Elizabeth Marek says
I think your cake might be a little narrow and you might need to use a board with supports to make sure it stands up
Evie Bowes says
Hi! My first baby was IVF- I know the journey! I am having to go dairy free due to second baby and BF.. I wondered if I used a dairy free butter like nuttelex and a dairy alternative like almond milk to make the buttermilk- would I ruin the cake?
Elizabeth Marek says
Yes you can use those alternatives! Sending you tons of baby dust <3
Shuqing says
Hi Liz! I'm thinking to make this cake with fondant (cover the cake and then a rainbow fondant decoration on top). Would the cake strong enough to hold? I'm using five wilton 6 inches cake pans which are kinda shallow. Based on my calculation. I should be able to cut your recipe in half. How should I adjust the baking time? Do you have any suggestions? Thank you so much!
Elizabeth Marek says
Yes you can cover in fondant and yes you can cut the recipe in half, the layers of cake will be very thin so they will bake faster.
Rachelle says
My 2nd child (now 18mo) was also an IVF baby. We struggled with other infertility treatments for 3 years... Infertility treatments can be such a wild and stressful ride! But what a gorgeous rainbow cake to bake for your handsome son. My son has squeezable cheeks too. I was actually looking for a cake to bake for my soon to be 7yo daughter, and loved that you shared your story 💗 I want to surprise her with it but I know I’ll struggle with making it in one day with her home. Can the layers be frozen and then defrosted the night before for assembly?
Elizabeth Marek says
Aww thank you! Im so glad you enjoy the personal sides to my posts as well as the recipe 🙂 You can definitely make all the layers ahead of time and then wrap them in plastic wrap and just put them in the fridge. No need to freeze them for such a short amount of time. Bonus, chilled cakes stack much easier than room temp cakes! Congrats on your journey <3 My daughter is almost 6! So we are in similar boats being pulled in a million different directions while trying to also bake haha!
Catherine says
Can I add food coloring to the water drip to make it a different color? I love the gold but would like to try a colored buttercream with a different colored drip.
Thank you!
Elizabeth Marek says
Yes you can use any color
Steph D says
Thanks so much for the wonderful recipe, I plan on making it for my niece's birthday this weekend. I have the pasteurized egg whites for the Easy Buttercream Frosting, would it be alright to use that in the cake as well? I noticed that it just had regular egg whites listed so I wanted to check. I also have to say that your easy buttercream is the BEST! Made it for my daughter's unicorn cupcake cake and it was fantastic!
Elizabeth Marek says
Yes its ok to use pasteurized egg whites in cake recipes
Julia says
Congrats on your little miracle baby! He's gorgeous!
On to the cake...I did a trial cake today as I'm going to be making this for a friend and my layers were pretty wobbly as I was stacking. Do you have any tips for when you are stacking? I see you didn't use any dowels or anything?? Your advice is appreciated!!
Elizabeth Marek says
Just make sure your frosting is flat and straight. Just takes a little practice but no special tricks. Thank you for the congrats!
Manel Azzabi says
Thank you for sharing your detailed recipe and tips for this gorgeous cake and God bless your little family! Here, the water ganache recipe says 6 oz of water for 6 oz of candy melts. In your previous ganache tutorials you said to use a ratio of 6:1. Is there a mistake somewhere? Should we use 6 oz or 1 oz of water for this drip? Thank you for clearing this out.
Elizabeth Marek says
Oops!! You are right! I don't know what I was thinking, I will update it asap.
Amelie says
I am planning to make this cake for my sister on her birthday but I just wanted to know why you said to use a dot of purple food coloring to make it white
Ps the cake looks great 😍
Elizabeth Marek says
It's a color theory trick we use in art. If you have yellow, you can reduce the yellow look by adding purple. A TINY TINY dot though. Too much and it makes the frosting grey.
Elise Ann Meyer says
Thank you for this professional and descriptive recipe. We made this for our granddaughter’s covid driveway birthday today. It came out gorgeous and the cake is delicious. I will post a pic on Instagram and tag you.
This is a complicated cake but if you carefully follow the food directions you can do it!
We used cream cheese frosting as it’s our family favorite and it was a great compliment to the buttermilk in the cake. The tangy dairy notes were so yummy.
Nea A. says
Hi Liz!
I was wondering if I can use a pastry flour (bob’s red mill unbleached fine pastry flour) instead of cake flour for this recipe or your brown butter cake (my fav)?
Thank you!!
Nea
The Sugar Geek Show says
Pastry flour is a bit higher in protein than cake flour so your cake might be a bit tougher but it should still be ok <3
Stacey Verley says
I am so happy for your miracle baby! You seem like a very loving, kind and caring woman and I am so glad your dream came true! You've taught me so much since I have begun my baking "career" and I am so appreciative. You probably have no idea how inspiring and talented you are, but you most definitely are! Thank you for everything you do and everything you have taught all of us that follow you! Best wishes and God bless your beautiful little family!!!!
The Sugar Geek Show says
Thank you so much Stacey <3 I really appreciate your comment <3