I've used soy flour for years, but never as the only flour in a recipe. I usually replace about 1/4 cup of wheat flour with 1/4 cup of soy flour. Also, 1 heaping tablespoon of soy flour will replace 1 egg in any baking recipe (well, almost any recipe--don't think it would work w/angel food cake
). I didn't believe this one until I tried it, but it actually works.
btw, cookie dough or cake batter will taste decidedly weird with soy flour in the mix, so you might want to warn any small people who are hanging around salivating . . . after baking, the cake, cookies, whatever, tastes completely "normal", no taste of soy at all. Hope this helps.