This post may contain affiliate sales links. Please read my disclosure policy.
Turn simple white cake mix into something magical for your next big event! This easy Rainbow Cake pairs perfectly with buttercream frosting.
Rainbow Cake | Made Easy!
You might have seen this trendy cake around social media! It’s super fun and perfect to make for parties. The cutaway, revealing six layers of different colored cake, is my favorite part. It might intimidate you, but don’t let it! My Rainbow Cake recipe is made easy by using white cake mix and food dye. Of course, you could make this completely homemade but that’s up to you! Pair it with my vanilla buttercream and rainbow sprinkles and you’ve got yourself a showstopper.
Main Ingredients Needed
Gather up these ingredients plus a couple of 8-inch round cake pans to start making this Rainbow Cake recipe!
- White Cake Mix – I used two whole 16.25 oz boxes of Betty Crocker Super Moist White Cake Mix. Feel free to use a brand that you like or a homemade cake recipe that makes six 8-inch cake layers (you could double my vanilla cake recipe and divid accordingly).
- Eggs, Oil + Water – these are to make the cake mixes! Follow the directions on the box you bought.
- Food Coloring – I used gel food coloring and a little goes a long way! Red, orange, yellow, green, blue and purple are all of the colored I used.
- Rainbow Sprinkles – these are optional and are used to decorate the outside of the cake.
For the Frosting
- Butter – this ingredient puts the butter in buttercream… cheesy jokes aside, make sure your butter is softened before making this recipe.
- Vanilla Extract – this recipe calls for vanilla extract for flavor but it’s not hard to experiment with this.
- Milk – this helps bind all the ingredients together and helps give this frosting its signature texture. Use as much or as little as you need!
- Powdered Sugar – we have our fats and flavoring down, so this ingredient is all about bringing that perfect sweetness to the frosting.
How to Make Rainbow Cake
For full details on how to make Rainbow Cake, see the recipe card down below 🙂
Step 1: Preheat + Prep
Preheat oven to 350 degrees. Line 6 8-inch cake pans with parchment paper around the bottom and spray with nonstick cooking spray. Set aside.
Step 2: Make Cake Mix + Divide
In a large bowl, make two cake mixes according to package directions with eggs, oil, and water. Divide batter into 6 even portions. You can do this by eye or weigh the batter out and divide it by 6.
Step 3: Dye Cake Batter
Using the gel food coloring, color each bowl of batter brightly to make a rainbow using red, orange, yellow, green, blue, and purple.
Step 4: Bake + Cool
Pour each colored batter into the prepared pans and bake for 13-17 minutes. Cool completely before frosting the cake.
Step 5: Make Frosting
Measure out the butter, powdered sugar, and vanilla into a large bowl or the bowl of a stand mixer. Using a hand or stand mixer, start to combine the butter into the powdered sugar. With the mixer on, slowly stream in your milk tablespoon by tablespoon until it starts to come together and look creamy. If it hasn’t come together, add another tablespoon, mix and wait it out.
After about 2 or 3 tablespoons, your frosting should be thick enough to hold its shape, but light enough to have a butter knife or rubber scraper run through it with ease.
Step 6: Assemble Rainbow Cake
Starting with the red cake on the bottom, layer the cakes up with vanilla frosting in between starting with red and ending with purple (the order goes red, orange, yellow, green, blue then purple).
Using the remaining frosting, frost the exterior of the cake smoothly. (If you want to do a crumb coat and refrigerate first and then finish the cake off with another layer of frosting, feel free to do that.)
Decorate with rainbow sprinkles and serve.
Loved this Rainbow Cake? Try these other fun recipes:
This Rainbow Cake was so fun to make and even more fun to eat. I loved the look on my kid’s faces when we cut into it. Purely magical!
The printable recipe card is down below, enjoy!
Rainbow Cake
Ingredients
For the Cakes:
- 32.50 oz boxed white cake mix two 16.25 oz. boxes (I used Betty Crocker Super Moist)
- eggs, oil and water amount according to boxed intructions
- gel food coloring in six colors
For the Frosting:
- 1 cup butter softened
- 4 teaspoons vanilla extract
- 2 pounds powdered sugar
- 4 tablespoons milk give or take a few tablespoons
- rainbow sprinkles optional
Equipment
- 8 inch cake pans
Instructions
Make the Rainbow Cakes:
- Preheat oven to 350 degrees. Line 6 8-inch cake pans with parchment paper around the bottom and spray with nonstick cooking spray. Set aside.
- In a large bowl, make two cake mixes according to package directions with eggs, oil and water. Divide batter into 6 even portions. You can do this by eye or weigh the batter out and divide it by 6. Using the gel food coloring, color each bowl of batter brightly to make a rainbow using red, orange, yellow, green, blue and purple.
- Pour each colored batter into the prepared pans and bake 13-17 minutes. Cool completely before frosting cake.
Make the Frosting:
- Measure out the butter, powdered sugar and vanilla into a large bowl or the bowl of a stand mixer. Using a hand or stand mixer, start to combine the butter into the powdered sugar. With the mixer on, slowly stream in your milk tablespoon by tablespoon until it starts to come together and look creamy. If it hasn’t come together, add another tablespoon, mix and wait it out. After about 2 or 3 tablespoons, your frosting should be thick enough to hold its shape, but light enough to have a butter knife or rubber scraper run through it with ease.
- Starting with the red cake on the bottom, layer the cakes up with vanilla frosting in between starting with red and ending with purple. Using the remaining frosting, frost exterior of cake smoothly. (If you want to do a crumb coat and refrigerate first and then finish the cake off with another layer of frosting, feel free to do that.) Decorate with rainbow sprinkles and serve.
Cute! I can never get my layers to turn out flat. What’s the trick?!
Reminds me of the one my late grandmother made for me when i was a teenager !
This cake is adorable! And so easy!