I'm a cake decorator in upstate NY, and my husband is currently deployed to Afghanistan. His birthday is in about a week and 1/2, so I'm making cakes in a jar tonight to ship out tomorrow. Nice and fresh. My question, is does anyone know about canning buttercream icing? I would love to add a little icing to these jars, or even send some home-made over, but I don't want it to spoil. It's averaging 10 days for a package to reach him. Thoughts?

This is a very sweet idea for you to attempt! I think that if you use an all shortening, milk-less butter cream recipe then it won't spoil, I think, I'm almost positive actually. Or you could do royal icing with meringue powder(which isn't the same as frosting, I know) but I'm pretty certain that won't spoil either. These are just ideas, see what other cakers have to say and then let us know! Good Luck!