What should I use instead of amaranth flour in these macaroons? I have barley, spelt and various wheat flours, plus some quinoa flakes. Gluten i...

I'd probably go for your most basic all-purpose flour. Maybe cut it with a little spelt--that would add a nice nutty flavor, which is mainly what the amaranth lends. I've also made these cookies with brown rice flour, sorghum flour, and white rice flour, all of which work quite well in place of the amaranth. Enjoy! I'd love to know how they turn out for you!