I think this what we use -- its a powder, but we buy it at whole foods. And I wouldn't say it consists of "chemicals" anymore than baking soda is a "chemical," but I digress.
It works great -- I haven't found anything that compares. And while expensive, a box lasts us 6 months or more. We use it for pancakes and other baked goods that aren't cooked for very long (see discussion below).
Speaking of which -- have you checked regarding whether your DN can have real eggs in baked goods? My daughter (who is very allergic to eggs) can tolerate 3-4 eggs in cakes or cookies as long as they are baked for 350 degrees for 15 minutes or longer. It breaks down the egg protein so much that her body doesn't recognize to fight it. (She could never have a souffle or something, though.)