I was wondering if anybody has painted on a cake and if so what do you use? I've read vodka, lemon extract, and cocoa butter. What works the best? Also, where would one get cocoa butter?

You can get cocoa butter from online resources. I know I have seen it at chefrubber.com.

As far as what is best? That is all personal preference. My preference is airbrush colors.

Ditto TexasSugar...I use airbrush colors straight from the bottle or regular Americolors mixed with vodka if I need a little more open time and everclear when I want it to dry immediatly. I use vodka or everclear because when you price it per ounce with lemon/vanilla extract it is much cheaper.

TexasSugar ... for painting do you use the airbrush paint directly with a brush?
It does not have to be mix with anything? Thank you in advance for your answer!

I use it straight out of the bottle. It's already thinned down, and it dries really well.

I have an airbrush, but really I've used my airbrush colors more with paint brushes than I have with the actual airbrush.