rainbow fairy cake - how to decorate with a rainbow?

[wakesandquakes]

DD wil be six soon and I'm planning a rainbow fairy cake (until I work out this is actually way too complex and actuallly a smartie cake is a brilliant idea). I had planned to buy some blue roll out icing and cover the cake with that and then make a rainbow (somehow) on one corner (or possibly cut a round cake in half and stick it on its side - this turning it neatly into a rainbow-shape....). Stick some colour print out of fairies round the edge and taa-da! The only problem is I haven't worked out how I can do the rainbow bit without spending a fortune of stuff I'm only going to need a tiny bit of.

Any ideas of how to do this (apart from recommending going straight to Plan B?)
Thanks

I made a rainbow cake years ago. Unfortunately can't remember the details exactly, but I think I used marzipan for the covering coloured with food colouring as it was easier to do the 'icing' in stripes. Of course you need several bottles of colouring, but I guess they last for ever & are useful for kids cake decorating anyway. Actually, IIRC, my 'rainbow' came in red, blue, yellow & green stripes.

The cake bit was the largest circle tin I had cut in half, sandwiched together & then a smaller circle taken out the bottom, if that makes sense.

I think smarties would look great! easier to get neat lines than with strips of coloured icing, plus oyou wont have to buy lots of paste colours to colour the icing. stick the smarties onto your iced cake with royal icing or buttercream.

You can buy a box of several colours of ready to roll icing. Small amount of each colour.
Think it is droetker.
I used it last year for dd's birthday cup cakes. She had the balloons from the film UP.

These are not what you describe but look like a lot of fun if you would be cutting a cake at a party rainbow cake

And these look manageable here especially making the rainbow out of smarties!

Some great ideas! Now I need to work out how creative I am feeling and how easy it is to get the stuff to do it all. Carrots that website is very good - most impressive what some folk can achieve. But I do like the idea of smarties/M&Ms etc as an easy way of getting the effect. Does anyone know whether the colour 'bleeds' and therefore would need to be done at the last minute (not very practical for the logistics of the birthday if I'm being honest) so I'd probably look at the marzipan / buy-it-off-the-shelf-in-little-packets-option instead. Any experience with the whole smartie stuff - does it depend on the type of icing?

I'd like to think I'm a bit creative (I'm not), but I do like to assemble stuff. (if it's easy to do...)

This looks like one of the simpler idea's

media.cakecentral.com/modules/coppermine/albums/userpics/472883/normal_Erikas_Rainbow_CakeSmall.jpg

I would expect the colour to bleed if put on icing as it is water based...but that is an educated guess rather than fact and happy to be corrected.

Smarties will bleed and fade and go soft if prepared to far in advance.
I have used butter icing all over the cake and stuck the smarties on.
You would get a more proffessional finish with ready to roll icing, depends on what you want really.

I have used butter icing and smarties and it stayed good for at least 24 hours, if not longer. The smarties did eventually go soft and the colour did bleed but not incredibly fast. If the party was the afternoon you would be fine doing it in the morning or probably even the night before.
HauntedLittleLunatic's link looks excellent and manageable though if you are wary.

Well that I ended up doing is this:

• 10 inch carrot cake
• 1.5 lb blue ready coloured and ready to roll icing
• pack of skittles (rainbow coloured - one line around the edge, one line around the bottom)
• I made a rainbow out of chewy tube sweets - miraculously found in the next corner shop but one! - trimmed, arranged in rainbow colours, pinned together with pins, tied in a rainbow shape with cotton, weighed down over night under a chopping board, then stuck with cocktail sticks in each one to stick in the cake
• blob of cream to act as 'clouds' to cover the join where the rainbow stuck in the cake
• flying fairies! - I photocopied a page of them, covered them with selloptape (to make them stronger), cut them out and stuck them on wire to make them fly over the rainbow ....

Looked good (according to Dd age almost 6!).

It sounds fab - can you put a photo on your profile?

I've not got a photo, but this is the closest (and good for inspiration - a suggestion from Carrots), although I just used chewy tube sweets for the rainbow effect. www.coolest-birthday-cakes.com/coolest-somewhere-over-the-rainbow-cake-15.html

The fairies sticking out on wires looked a lot like this: somethingtocelebrate.files.wordpress.com/2009/11/img_1722.jpg

All in all surprisingly straightforward (particularly with hindsight). The trickiest part was getting the tube sweets to make the rainbow. The prototype was discarded and eaten, but version 2 worked OK.

It's good to know that once a year I can be a little bit creative.....but that's it, until DS started saying he wanted a boat - but have 6 months to channel creativity for that.!