I have checked other posts for this but cannot find the answer.

I want to bake from scratch, a 6 layer Rainbow cake,which I think with icing between layers would make it 5-6 inches high.

Also need to know how much butter cream I would need for in between layers, and over the whole of the cake.

Thank you

Would any of this help?

https://www.google.com/search?q=rainbow+cake+instructions&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Thank you,we have tried one of Betty Crockers and was not totally happy,I was hoping someone here might have had a tried and tested recipe.Though there are a couple of scratch cakes on the link page you have given,that would seem to be good.

i made this rainbow cake with toba garrett's moist yellow cake, http://www.epicurious.com/recipes/food/views/Moist-Yellow-Cake-109358

i love this cake plain, but the food coloring takes away from the great flavor.  i tried to put some back by adding two extra teaspoons of vanilla.

the whole cake pictured was a practice cake.  the slice is what i ended up making for the party.

these are my notes:

each layer is about 0.5" tall.

~240 grams batter per 8" round pan

350F
baked 4 pans, ~12.5 min
baked 2 pans, 12 min

i used americolor gel colors

super red (3 drops) + red red (1 drop)
electric orange (3 drops)
lemon yellow (3 drops)
leaf green (3 drops)
royal blue (3 drops)
violet (3 drops) (better than regal purple)

the practice cake was iced with Whimsical Bakehouse House Buttercream.  i wrote in my notes that a half-recipe (~4.25 cups) is enough to fill two 8" 6-layer rainbow cakes.  i'm not sure if that includes icing the cake as well.  (sorry, it's been over a year since i made this cake.)

chestercheeto, didn't you have any trouble with the blue? I used a off-white cake recipe and Americolor Royal blue, but the little bit of yellow in the cake turned the mix green! What is your secret?

carrie, toba's yellow cake batter isn't very yellow.  if i had any problems with the blue, i think i would've put it in my notes.  but you can try adding a little violet to your yellow batter, that should whiten it.  and then add your blue color.  

I've used americolor to color a doctored yellow cake mix rainbow colors multiple times.  Each time I get bright, beautiful colors without issue.  Just remember the color batter is basically what the color of the cake will be, so make sure it's the right color before you bake!  I always add extra vanilla, and as far as I know it's not been an issue in changing the flavor of the cake (be sure to use americolor tulip (no taste) for the red!).  I can see how the more delicate flavor of scratch might be overwhelmed by the food coloring though.

ChesterCheeto and FrostedMoon, thanks for your suggestions. It has been blue headache for me this week. I did put a little Americolor Lilac in the cake batter. It looked just like I wanted. After baking, it had the color of moldy bread, but it tasted good. :)  I tried twice with hard candy to make "water splashes." Got green, a nice pretty green, but not what I wanted. Will just have to do some work arounds.

Good luck! Please post a picture when you make it.

AI used the wasc recipe from here. I can't remember how much buttercream I used but I know it was ALOT lol [IMG]http://cakecentral.com/content/type/61/id/3106984/width/200/height/400[/IMG]

When I made this rainbow cake, I first tried to use crushed berries to colour the batter but the colours were not vibrant enough, so I added americolor gels.

I did not put any filling between the layers, just a few dabs of simple syrup. 

Can you use ordinary milk instead of buttermilk?

I tend to find that the colour you use makes all the difference. Weaker, liquid colours completely alter the consistency of the batter. and even with good quality pastes I find that the baking time changes. For me...red seems to take longer to bake.