Help with icing!

[Pitapotamus]

I need some yellow icing to spread on a cake (jcb colour!) I have some Betty Crocker vanilla icing in a tub which is whiteish. If I put yellow food colouring in that will it work or will it all go horribly wrong?

Try a bit of it first and see how it looks. I have used the Betty Crocker icing and it's quite thick although I might add extra icing sugar to make it thicker.

Thanks very much. I tried it with gel colouring. It worked!