Rainbow Explosion Birthday Cake Recipe

Today’s a very special day… IT’S MY BIRTHDAY! This year to celebrate my 33rd birthday, I wanted to make my own cake. I have the had the privilege of meeting Amirah Kassem several times, working with her and hiring her bakery Flourshop a couple times. She’s the one who’s the mastermind behind the Rainbow Explosion Birthday Cake! (P.S. She has a book called The Power Of Sprinkles that we all need in our lives PLUS she sells her cake kits at Williams Sonoma).

I’m hoping I was able to do her proud this year when I made my own at home! I didn’t use her Cake Kit this time, but I did follow her guidance (and inspiration)! It was super fun and fabulous… and made a HUGE mess! ha

I started by using Duncan Hines Classic White Cake Mix and then followed some simple online recipe hacks to making that $2 box cake mix taste like a $6 slice you buy at the store (directions below)! Then I bought a Easy Layers Cake Pan Set on Amazon from Wilton – it’s a set of five, 6-inch pans which means you can divide one box of cake mix evenly so it’s super easy.

To color the cakes, I followed after Amirah’s lead and bought Chefmaster Neon Liqua-Gel Food Coloring to get bright, bold colors. WARNING: Be careful not to get on your hands because you’ll have to wash them A LOT to get it off. Once I mixed the cake, I divided into 5 Glass Mixing Bowls so I could color. I have to admit… I made the first cake by using only a few drops (3-5) and it came out significantly faded. So I panicked and made a second version with over double the food coloring which looked so much better, so I would go that route!

Once the cakes are cooked, make sure they cool down FULLY (to the touch and won’t crumble) before you start to assemble. If you’re making an explosion cake, you’ll want to start by cutting a hole out of the 3 middle layers. I was able to do this using a champagne flute! If you want just a regular rainbow cake (I made both), then you can skip this step overall. PRO TIP: To assemble, ice and decorate so much easier, do yourself a favor and get a Rotating Cake Turntable, it’s worth it. Then it’s just icing, layers between cakes and filling up the explosion tube with sprinkles before adding the top layer (with no hole in it).

After you have it successfully stacked and iced, then it’s the fun time. SPRINKLE PARTY!! Btw… I bought 2lbs of Sprinkles to make sure I wouldn’t run out and I made 2 cakes and still have about half left! The easiest way to get sprinkles to the sides is to not worry about making a mess and literally grab handfuls and just place them all around it until you cover ever inch of the white icing. You don’t even have to ice it to perfection, because the sprinkles will hide any imperfections. 🙂

You can check it all out in my YouTube video below!

Cake Box Hacks to Make it Taste Better:

  1. Replace Water with Milk (I used Almond Milk even)
  2. Replace Vegetable Oil with Melted Butter + Add MORE! (I used a whole stick)
  3. Add an Extra Egg (Also since we’re coloring the cake, you can keep the yolks)

Easy Vanilla Buttercream Frosting Recipe:


  • 1/2 cup solid shortening (I used butter flavored Crisco)
  • 1 stick of unsalted butter, softened
  • 4 cups sifted powdered sugar
  • 2 tablespoons milk or heavy cream
  • 1 teaspoon vanilla extract


  • In your Kitchenaid Stand Mixer, cream the butter and shortening on medium speed using the Paddle Attachment until light and fluffy for about 1 minute. Beat in vanilla and scrape down the bowl occasionally.
  • Gradually add powered sugar, one cup at a time, staring by mixing each cup on a low speed then beating well on medium speed. Scrape sides and bottom of the bowl after each cup of sugar is added. When all sugar has been mixed in, the frosting will appear dry and stiff.
  • Gradually add milk or heavy cream, adding small amounts at a time until the desired consistency is reached; continue to beat at medium speed until light and fluffy.

Recipe by Wilton.com

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