1) I have not yet found a vanilla extract that contains no gluten, corn, or potato (if you know of one, please let me know)
2) Fresh vanilla from the bean tastes amazing
You can buy vanilla powder already made. It comes in a little jar like this, and costs about $18/oz (yikes!)
Making your own vanilla powder is super-easy. Take one vanilla bean:
Cut it into smaller pieces, and put in a clean coffee grinder (these are pieces of vanilla bean added to some already ground vanilla)
Give it a whirl, and you wind up with vanilla powder
Just keep processing until it's as fine of a powder as you can get. You really want a fine powder, not chunks of vanilla bean. I've found my coffee grinder does not process all of the vanilla as fine as the commercially prepared version, but it's very close. What you see around the lip of the coffee grinder is what you are going for. The pieces you see in the bottom need another whirl or two.
I store the ground vanilla in that little jar I showed above, and refill as needed. I find grinding two beans at a time lasts me quite a while. I also use a little paintbrush (that I only use for vanilla powder) to get every last speck of vanilla out of the coffee grinder and into the vanilla jar.
It measures 1:1 with vanilla extract, but I tend to use slightly less (due to cost) and it still works great.
The best source I've found so far for vanilla beans is Beanilla.com- you can order from them directly, or through Amazon.com here