Can you bake in a Mason jar?
I don't want to can bread or cake, but I'm starting to think about my DD's birthday cake. We're taking friends to see the new Disney movie about Rapunzel, so I thought I'd make a tower cake set on a small sheet cake. I need something smaller in diameter than my smallest pan - can I use a 3C widemouth jar if I grease it well? Fill it with 2C of batter? Or less? Anything special I need to do to make sure it doesn't crack in the dry heat (put a pan of water in the oven?)?