The key to the very best gluten-free baked goods is Authentic Foods superfine brown rice flour; it is the Cadillac, or cashmere, of brown rice flours and is worth its weight in gold. It is not grainy like other rice flours, and bakes the most fantastic cookies, cakes, pie crusts, and so on. If you can't find it at your local natural foods market or Whole Foods, order it online. Both Ener-G and Bob's Red Mill brown rice flours will also work in these recipes, but they won't turn out quite as well. I do not recommend Arrowhead Mills brown rice flour, which I find too gritty. The brands of potato starch and tapioca flour or starch are not important; I find them all interchangeable.
4 cups superfine brown rice flour 11/3 cups potato starch (not potato flour) 2/3 cup tapioca flour (also called tapioca starch)
1. To measure flour, use a large spoon to scoop flour into the measuring cup, then level it off with the back of a knife or straightedge. Do not use the measuring cup itself to scoop your flour when measuring! It will compact the flour and you will wind up with too much for the recipe.
2. Combine all ingredients in a gallon-size zipper-top bag. Shake until well blended. Store in the refrigerator until ready to use.