<<Disclaimer: Verify this information before applying it to your situation.>>

Several people have already written asking me where you find amaranth flakes.
 I know you can buy toasted, rolled amaranth flakes online at
glutensolutions.com.  (I have no affiliation with that store; I just buy a
lot there.)

By the way, I've also had amazing luck with using "The Cake Doctor" recipes
with the Really Great Food chocolate cake mix (also available at
glutensolutions.com and, of course, I have no affiliation with either
company).  I doctor the mix according to various recipes in the book (usually
adding instant pudding, eggs, sour cream, etc.--it's not health food) and the
results are unbelievable.  Everyone eats it; no one can believe it's GF.

* Please remember some posters may be WHEAT-FREE, but not GLUTEN-FREE *