Tiered Rainbow Cake. No Tears Shed In The Transport.

On Thursday, my eldest son graduated from elementary school. They call it a “celebration” here. It was a lovely event. Casual ceremony, a wonderful photo slideshow of the students at all ages, and an amazing potluck dinner for all of the families outside on the green.

I was asked to make the cake for the celebration. At first I wondered if it was because people thought I was a good baker or if no one else wanted to do it. (I live in a town of incredible talent in the kitchen.)

No matter what the reason, I eagerly accepted. I have always wanted to make a big cake, but never really had an appropriate event to do one for.

I knew I would make a rainbow/tie dye cake, because it looks fantastic and feels festive. After doing the calculations, I needed 31 cups of cake batter and about 20 cups of icing. Here’s a Really fact. The icing required 10 pounds of confectioners’ sugar and 6 pounds of butter. Really? Really?

Yes. And it was flippin’ heavy. When I started assembling the cake on Wednesday, I started worrying about how on earth I was going to get it from my house, down dirt roads, to the school one mile away. Really worrying. (Really? Yes.)

The cake was safely transported. The key, which a friend told me, was to line the floor of the car with a non-skid mat. Worked like a charm. Aside from the muscle power required to hoist it to the car, into the car, out of the car and into the school, it was a piece of cake. HaHa!!

To accompany the cake I made letter cookies iced with royal icing. I used the cookie dough and icing from this post. I included the lemon extract in the cookie dough this time and the cookies were super yummy.

I also surrounded the cake with Funfetti Cupcakes. This recipe was different than the one I shared here. These cupcakes were denser and loaded with non-pareils. I loved them. I’ll post that recipe soon.

I’m going to share the instructions to make a tiered cake. The rainbow cake is also fabulous as a regular sized layer cake. That only needs about 5 cups of batter. :)

Tiered Rainbow Cake


2- 8 inch cake pans
1- 11×3 inch cake pan
1- 12x18x2 inch sheet cake pan
Wooden dowels
Clipper to cut dowels
A large offset spatula
Piping bags
Tip #32 star
Tip #18 star
Cake boards in 8 inch and 10 inch sizes
Cardboard large enough to cut out a 12×18 cake board from
Large Wooden Board/Platter to assemble cake on (I used a large cutting board that conveniently has handles)

Quantities of batter needed for each pan:

2- 8 inch pans: 3 1/2 cups in each pan
11×3 inch pan: 10 cups
12×18 inch pan: 14 cups

Baking times for each pan:

2- 8 inch pans: 30-35 minutes
11×3 inch pan: 60-65 minutes
12×18 inch pan: 45-50 minutes


5 boxes of white cake mix, with ingredients listed on the box to prepare. I used whole eggs in my batter.
5 boxes of vanilla pudding mix, 3 oz size (not the instant kind)
5 packets of Dream Whip
gel paste food coloring in your colors of choice. (A true rainbow has Red, Orange, Yellow, Blue, Purple and Green) I substituted undyed batter for the green.
Buttercream Icing
Colored sprinkles


Preheat oven to 350℉. Prepare pans for baking. (Make sure to super grease the pans.)

Prepare cake mixes according to directions, adding one packet of Dream Whip and one box of pudding per box of mix. I made enough batter to do one cake layer at a time. The two 8 inch first and then the bigger ones. I used a regular one cup measure to scoop out the batter.

3. For each cake, divide the batter equally into six bowls (make sure the bowl is big enough for you to give the coloring a good stir without making a mess).

4. Dye the bowls in rainbow colors (red in one bowl, orange in another, etc…). Mix well.

5. Pour the batter, one bowl at a time, into the pans layering one on top of the other. No need to stir. See note below if you want to do a true rainbow cake.

6. Bake for the specified amount of time for each pan size.

7. Let cool in pan for 10 minutes then turn out onto a cooling rack to completely cool.

Note: Directions for making a true rainbow cake (for the 8 inch round pans only. Or you can do the same for a 9 inch cake that is not part of the tier. Use one box of cake mix for each 9 inch pan. You’ll get an impressively tall and fun layer cake):

1. Pour 1/2 of red batter, then 1/2 orange, and then 1/2 yellow into one of the cake pans. As you pour the dyed batter in, wait a couple minutes until the colored batter has spread a bit. (Let it spread by itself). Then slowly add the next color. Finish with yellow. (See batter order for each pan below)

2. When you’re three colors in, start doing the reverse with the other pan. So pour 2/3 cup purple, one cup blue and then one cup green into the Second pan.

3. Since I’m going in rainbow order: red, orange, yellow, green, blue, purple, I got from red to yellow in the first pan, then purple, blue, green in the second. (This is so that your two pans are equal if your measurements aren’t exact (and they’re not likely to be)).

4. Continue with first pan with one cup green, one cup blue and the remainder of the purple.

5. Slowly add the first color and let spread a bit. Then add the next couple of colors slowly until each spreads a bit.

The quantities below are based on using two boxes of cake mix to fill two 9 inch layer pans. Don’t use these quantities for the 8 inch layer cake. 

Pan 1

2/3 cup red
1 cup orange
1cup yellow
1 cup green
1 cup blue
Remainder of purple

Pan 2

2/3 cup purple
1 cup blue
1 cup green
1 cup yellow
1 cup orange
Remainder of red (approx. 1 1/3 cup)

6. Your pans will be about half full. This makes 2 thick layers of cake.

7. Bake 8 inch cakes about 30 minutes. (9 inch needs about 45 minutes if they have a full box of mix in each). Check for doneness. Let cool 5 mins before removing from pans. Let cool completely.

Here is a Rainbow Cake I made awhile back to give you an example of how a smaller cake looks. Pretty cool, huh?

Directions for tiering and decorating the cake:

1. Approximate where the 11 inch cake will be placed on top of the bottom cake layer. Insert 8 dowels, straight down, in a circle into the cake within this area. Place an additional dowel in the center of this circle. The dowels ensure adequate support for the cake layers that will be on top. Use a knife to make a scratch to mark the correct height needed for the dowel (the height of the cake layer). Pull out dowels. Cut the dowels along the knife scratch. Reinsert into cake.

2. Repeat the dowel insertion process with the 11 inch cake (You can use the leftover pieces of dowels) using 6 dowels in a circle to support the 8 inch layer cake that will sit atop of them.

3. Prepare icing. I used the buttercream recipe from here. I needed to make 6 batches to have enough to ice and decorate all of the layers.

4. Place one of the 8 inch cake layers on the 8 inch cake board. Ice the top and place the second layer on top. Now you are going to do what is called a crumb coat. This is to prepare the surface of the cake before further decorating it. Apply a thin coating of icing over the cake to seal in the crumbs and then refrigerate the cake for about an hour. This step, which I always like to skip because I am an impatient beast, is really worthwhile as it helps immensely in achieving a smoother surface. It also helps to prevent crumbs getting onto your final icing surface.

5. Crumb coat the 11 inch cake, which you have placed on the 10 inch cake board. Refrigerate.

6. Place 12×18 cake on its cake board. Crumb coat. There was no way I’d ever find room for that size cake in my fridge, so I had to skip chilling it. If you have space in your refrigerator, by all means chill the cake.

7. Place 12×18 inch cake, with it’s cake board under it, onto the serving platter. (As I mentioned, I used a large cutting board and covered it in tin foil).

8. Ice the cake and smooth the top and sides. To do this, dip an offset spatula into hot water. Quickly dab it on a paper towel to remove excess water and then slide it across the surface of the cake. Scrape the icing that came off on the offset spatula into a small bowl. (You can mix this small bowl into the big bowl of icing later so as not to waste any.) Continue smoothing the top and sides of the cake with a hot spatula. I have never been able to achieve a really smooth surface, but I try. One of these days maybe. Remember, the shell border, sprinkles, and other piping hides a lot!!

9. Ice the 11 inch cake and place it on top of the bottom cake layer. Smooth the top and sides.

10. Ice the 8 inch layer cake and place on top of the 11 inch tier. Smooth the top and sides.

11. Pipe tip #32 shell borders along the bottom of each tier. Pipe tip #18 shell borders along the top of the tiers. Using tip #32, make swirls around the top of the cake. Use tip #18 to make zig zag garlands up and down the sides of each tier.

12. Sprinkle all of the shells and garland with the colored sprinkles.

13. If you baked letter cookies, spell out your message around the cake.


Here’s the cake in the car ready to go. Heart is thumping hard at this point. I’m a nervous wreck.

Now you stay still in there. Don’t you dare fall apart on me!

Whew. We made it to the school.

I’m cutting the first piece. I studied “how to cut wedding cakes” in a Wilton Cake Decorating magazine before setting off to the school.

Let’s add music.
Simple Minds-Celebrate

Kool & The Gang-Celebration


About I Sing In The Kitchen

Music obsessed cooking freak whipping up fab food one song at at time.
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14 Responses to Tiered Rainbow Cake. No Tears Shed In The Transport.

  1. holy, holy, holy heavens. That is SOME cake. YOu deserve a ribbon!
    Wow; you have really outdone yourself. :-) Congrats to you, Trisha, on such a big feat!

  2. Sarah says:

    Tricia, you are the WOMAN!!!! I was thinking of you on Thursday!!! I knew it would all work out!!!! What an amazing feat. Had I known you 9 years ago, I would have had you done our wedding cake!!!

  3. Sarah says:

    Whoops, My grammar was off…… “I would have had you do our wedding cake.” :)

  4. Stephanie says:

    This is absolutely amazing! The cake looks beautiful. Congrats on the school graduation :)

  5. liz2024 says:

    YOU ARE ONE ROCKIN AWESOME MAMA! Good Job Tricia and I am glad to have this tutorial now!

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