Cake:

  • 2 box(es) White Cake Mix
  • 4 drops Food Coloring (Use As Much As Needed To Attain Desired Color

Frosting:

  • 4 packages Cream Cheese (8 Oz. Package)
  • 1 cup Butter
  • 5 cups To 6 Cups Powder Sugar (confectioners Sugar)
  • 1 Tablespoon Vanilla

I use Ateco food coloring, which can be found at www.atecousa.net

For the cake, make one box cake mix according to the directions on
the box. Separate batter into 3 bowls with roughly about 1 cup of cake
mix per bowl. Add desired food coloring to each bowl (purple, blue,
green).

Bake cakes in round pans according to box instructions, but make
sure you check the cake about 10 minutes before it’s supposed to be
done. With less mix in each pan, they can cook faster.

Repeat for the remaining colors (red, orange, yellow). You will now have six layers of different colors.

For the frosting, mix together softened (room temperature) butter
and softened (room temperature) cream cheese until well combined. Add
vanilla. Combine. Slowly add in powder sugar.

(After the 5th cup of powdered sugar, taste the frosting and see if
you would like it sweeter. I tend to use the full 6 cups, but some
prefer the frosting less sweet.)

Cake assembly:

I try to first level each layer of cake with a large bread knife.
For the rainbow cake especially, if all the layers are level, then they
will evenly display when you cut into it.

Start with the PURPLE layer first. Put the purple layer on your cake
stand or plate. Add enough frosting to cover the layer and some to
spill over the edges, anywhere from 1/2 to one cup of frosting. Run the
flat, straight side of a knife around the cake to smooth out the edges.

Add the BLUE layer of the cake. Put frosting in the middle, start
spreading out frosting with the flat, straight side of a knife so that
it covers the cake and falls out over the edges. Then run your knife
around the outside edge of the cake to smooth out the sides.

Put the cake into the fridge for at least 2 hours or freeze for 1 hour.

Repeat with GREEN layer, then YELLOW layer.

Put cake into fridge for at least 2 hours or freeze for 1 hour.

Repeat with ORANGE layer, then RED layer.

Cover cake with frosting and run the flat, straight edge of a knife around the edges of the cake to smooth out the frosting.

(It was important for me to freeze the cake between layers for a
couple reasons. The cake can get really heavy by the time you are
adding the 4th, 5th, and 6th layers, but if it is somewhat frozen at
this point, it will not get schmooshed or crushed. Also, it is much
easier to frost the cake when it is solid, or not wobbling all over.)

Once you have finished frosting the cake, add any decorative touches or words that fit your occasion! Good luck!

(I set the skill level as difficult, but ONLY because of the time
involved. Truly, anyone can do this, and do it well! It just takes a
little patience. The end result is SOOO worth it!

Share with your friends!

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Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. I was wondering if the frosting with this food coloring makes your tongue a color when u eat it? I made a blue icing for a border using wilton gel color and i tasted a tiny drop of it and my tongue turned so blue! Does this food colring do that?? Thank you! Love your blog!

    1. It depends on how much you use, the quality of product you use, and the color used. Yes, food coloring can tint your fingers and tongue… 🙂

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