The Ultimate Rainbow Birthday Cake with Whipped Nutella Icing

Last weekend was my roommate's birthday, and since she is a super awesome roommate, I wanted to make her a super awesome cake.

Cake:

-3 Boxes White Cake Mix + whatever the box calls for the make the cake. If it calls for oil, I always substitute an equal amount of butter, and if it calls for water, I substitute whole milk. You will be rewarded with a much fluffier, moister cake.
-Gel Food Coloring

Icing:

-Tub of Nutella (the small size)
-Tub Chocolate Icing (whatever kind you like)
-Tub of Cool Whip
-1 package chocolate pudding mix

1. Preheat oven to 350F (always, duh).
2. Prepare one box of cake mix according to package directions (or with butter subbed for oil and milk subbed for water if you want your cake to taste better). Divide the cake mix into two bowls. Add red and blue to one bowl (to make purple) and blue to the other bowl. Mix thoroughly. My purple didn't look too hot here, but it turned out pretty!

2. Line 2 round cake pans with tin foil. This is a huge time-saver! It allows you to gently lift your cakes out of the pans so they can cool while you bake your second batch. Additionally, you don't have to wash the pans, and I like to wash as few pans as possible.

 3. Bake according to package directions. When done, remove cakes on their tinfoil liners and set aside to cool.

4. Make your frosting while the first cakes are baking so it can sit in the fridge before you frost your cake. Make the chocolate pudding according to package directions. When you're done, eat 1 cup of pudding (at least that's what I did). The second cup of pudding gets mixed together with the entire tub of Nutella, the entire tub of chocolate frosting and the entire tub of Cool Whip. Put the bowl of frosting in the refrigerator on the highest shelf (I hear calories are scared of heights and jump out).

4. Prepare second box of cake mix, divide, and add gel colors to make green and yellow. Bake. Remove cakes and set aside to cool.

5.  Same thing again! Just with red and orange. Bake, and let your cakes cool. They need to be cool before you frost them or the frosting will melt all over the place!

6. When all 6 of your cakes are cool, stack them in reverse rainbow order - purple, blue, green, yellow orange, red. They make look kind of lumpy, floppy and discolored (see below), but don't worry! We will fix that!

7. Take a large, serrated knife and cut vertically into the cake. Slide your knife around the circumference with short, rapid strokes to remove the outer 1cm or so of cake. It is important to use a serrated knife for this step. Using a non-serrated one will just pull chunks of cake off instead of making smooth cuts, and you will end up with a mess. 

8. Remove the cut off bits, and you should have a tall stack of gorgeous, rainbow confection!

9. Okey doke, now disassemble your cake. Leave the purple layer on whatever plate you want to serve the cake on. Put the other cakes off to the side. Using a small rubber spatula, spread icing on the top and sides of the purple layer.

 10. Gently place the blue layer on top of the frosted purple layer. Make sure the cakes are centered on top of one another. Use the spatula to ice the top and sides of the blue layer. Repeat with the rest of the layers.

11. When you have frosted all the layers, smooth out any lumps and bumps with a knife, and decorate however you'd like!  I piped on some green frosting (I kind of ran out of patience at this point, so I didn't do a great job with the green frosting!), and added some sprinkles. It says "Yay, Megan!," because she's an awesome roommate!

How awesome is that?  Every time I open the fridge I admire how freaking cool it looks and remind myself what an excellent baker I am. Sometimes self-indulgent congratulations is necessary and proper.

Note: I think this would work equally as well with 2 boxed cake mixes divided into thirds if you didn't want your cake to be quite as tall. However, I think the height adds an element of drama, and a rainbow cake should be dramatic!