Best gluten free flour recipe

These are all so great. Thanks! The anti-caking would be for when grinding the legumes because of the high fat content.

Bob's Red Mill is a good source for all sorts of glutenfree flours, from legume and rice to harder-to-find ones like teff and millet. For my own baking, I never use xanthan or guar gums because they don't agree with me. Instead, I tailor my own flour mixes to each recipe I make. It usually breaks down to the following ratios, give or take small adjustments depending on the recipe:
- 30% starch (usually tapioca or potato, sometimes arrowroot or corn)
- 20-30% sweet rice flour
- 15-20% ground flax or chia
- the rest nut meal, sorghum flour, millet flour, buckwheat flour, or some mix of the above

Millet adds wonderful color to glutenfree baked goods, even if you only use a small amount in your recipe. For yeasted breads, I'll increase the flax or chia seeds and often add 1-2 tsp psyllium husk.

Here's my recipe for Raspberry Multigrain Muffins, where you can see I've adjusted the ratios slightly to keep the muffins light and airy while they're packed with multigrain goodness. (The extra sweet rice flour helps with this.) I often sub at least 15-20 grams ground flax for some of the amaranth, since amaranth is rather expensive. http://food52.com/recipes/14662_raspberry_multigrain_muffins

If I grind more than need immediately, I put the rest in the freezer. Why would you use an anti-caking agent?

do you think you would notice using an anti-caking agent in the final product if you added it when grinding the legumes?

If you want to make small amounts of flour from whole grains and legumes, you can use an electric coffee/spice mill sucessfully. Just don't overgrind the beans, because of the high fat content. You can also make nut meals (food processor is good for this). There's a video on food52 showing how to make almond meal (or butter, again because of the fat content -- you have to know when to stop!).
I have found that Indian markets have a wide variety of whole food flours at reasonable prices -- bean (besan is chickpea flour), grain (sorghum and blends), for instance.
Asian markets are good for the starches, and I have found brown rice flour there too.
If you need large quantities, small natural food stores may be helpful, as they will usually be happy to order what you need, in quantities or varieties that may not be on the shelf.
Check the food52 cook beyondcelery for her recipies on the site and on her blog -- some of my favorites!

I keep a gluten-free flour mix on hand that's about 65-70% starch (tapioca starch and sweet rice flour) and 30-35% whole grain (sorghum flour and brown rice flour). Depending on what I'm making, I might add in more of one of the whole grain flours along with the mix the same way you might substitute in some whole wheat flour in an all all-purpose flour recipe.

You don't need to dehydrate and grind your own legumes. Chickpea flour is widely available, and there's also lentil flour and even green pea flour out there. Teff, millet, and quinoa make hearty whole-grain flours as well, though they might be a little harder to track down.

Here's what I've been using. It's the closest I've found to a mostly whole grain flour, and the results are good.
http://www.make-your-own-bread.com/gluten_free_flour_mix.html