Rainbow Cake

When my blogging buddy Jen from 3 Little Monkey’s posted this birthday cake she made for her son, I knew I wanted to give a try for my big boys! All three of my guys have birthdays within 10 days and this is the first year that the two big boys would be celebrating their parties together. The cake turned out really great! I stressed about it falling over onto the floor, but it was surprisingly easy to make! Thanks for the great inspiration Jen! Check our her cake here.

Rainbow Cake

2 boxes white cake mix
6 eggs
1 cup water
2/3 cup vegetable oil
zest of 1 orange + juice of the orange
zest of 1 lemon + juice of the lemon
zest of 1 lime + juice of the lime
1/2 cup fresh or frozen raspberries, mashed
1/2 cup fresh or frozen blueberries, mashed
1/2 cup fresh or frozen blackberries, mashed
Wilton’s gel icing colours in- red, orange, yellow, green, blue, and purple
6 bowls
6 disposable 8″ round foil cake pans (check your dollar store, I couldn’t find 8″ so I used 9″ pans)

Fruit ready to go


Make the batter for the cake as directed using the 6 eggs, 1 cup water and 2/3 cup vegetable oil. Scoop 1 cup of cake batter into each of the 6 bowls.

In the first bowl, mix raspberries and 1/4 tsp red colouring into the batter.
In the second bowl, mix blueberries and 1/4 tsp blue colouring.
In the third bowl, mix blackberries and 1/4 tsp purple food colouring.
In the fourth bowl, mix orange zest, juice, and 1/2 tsp orange colouring.
In the fifth bowl, mix lemon zest, juice, and 1/4 tsp yellow colouring.
In the sixth bowl, mix lime zest, juice, and 1/4 tsp green colouring.

Prepare the six 8″ cake pans by greasing and flouring each generously. Spoon and spread each colour of batter into it’s own cake pan.

Bake in oven, preheated to 350 degrees for approximately 20 minutes, or until tops spring back when touched lightly. Allow to cool completely.


1 cup butter, softened
2 – 8 0z. packages cream cheese, softened
8 cups confectioner’s sugar
2 tsp vanilla or lemon extract (I used vanilla)

Cream butter and cream cheese until smooth. Add sugar and extract. Beat on high speed until smooth, light and fluffy. (This icing is so yummy!)

Put first layer of cake on a sturdy cake plate. Frost the top. Add second layer and frost the top. Add third layer and frost the top. I followed Jen’s idea and put mine in the fridge for 1/2 hour to harden a bit so the cake wouldn’t move around when I added my next three layers. Then add the next three layers, frosting each until last layer is on top.
Frost the entire cake decorate any way you like. I used fondant coloured orange and blue, cut out circles for the sides and each boys name and age for the top (blurred for privacy). I used a Diago candle and piped grass with the wilton grass tip around the bottom of the candle.
Refrigerate overnight.

Enjoy! Each layer has it’s own yummy fruity flavour!



  1. MealPlanningMama says:
  2. One Love Mama says:
  3. Redbonegirl97 says:
  4. 3LittleMonkeys says:
  5. Heather says:
  6. Miz Dinah says:
  7. Mama Ash says:
  8. My youngest would LOVE this cake. She is obsessed with rainbows!

  9. My oldest son gets so excited when he sees a rainbow. I should make him this cake. He’d love it.

  10. Debbie White Beattie says:

    I can’t believe you went through all that for a multi color cake. That’s too much work, I’d probably buy it.

  11. Judy Cowan says:

    My niece keeps talking about a rainbow cake for her birthday and I am guessing this might be what she is talking about. I think she is hinting & hoping I would make her one..lol

  12. kathy downey says:

    I would love to try this cake some time,so pretty !

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