Gluten-free flours
First of all, wheat flour is NOT gluten-free.
Secondly, barley flour is also NOT gluten-free.
It's been a while since I worked at a bakery where my co-workers purchased ordinary cake (wheat) flour for a bakery that serviced people with gluten intolerance. My apologies for getting into an argument with the supervisor over the less than delicate flavor.
Here's a list of flours that are gluten-free (see Bob's Red Mill)
almond meal
flax meal
rice flour
corn flour
amaranth flour
quinoa flour
chickpea (garbanzo bean) flour
oat flour
coconut flour
cricket flour
teff flour
All of these flours have an excellent flavor, although, each one is a bit different than the "bland, boring rice flour"...
Here's a list of binding agents
cooked tapioca
cornstarch
rice starch
cooked banana
xanthan gum
Various vegetable powders make for excellent flavors and colors
carrot powder
alfalfa powder
crumbled dried
beet powder
dried blueberries
