While there are many worthy options, I use Bob’s Red Mill products for this mix. Importantly, I have heard that quality is lacking in some brands of xanthan gum, so I do highly recommend Bob’s Red Mill or another reputable brand for this product. Only a small amount is required, but it is integral to the recipe.
3 cups rice flour (see notes)
1 1/2 cups tapioca flour
3/4 cup potato starch
1/2 tablespoon salt
1 tablespoon xanthan gum
Mix all ingredients and store in a large zip-top bag.
If you bake gluten free regularly, consider doubling the recipe. Use cup for cup as you would wheat flour. Most of the baked products I post are items that I have cooked both the traditional and gluten-free way with much success.
I started out making this mix with all white rice flour. Now, I often use half white and half brown rice flour for the added whole grains. My favorite combination, however, in order to balance the benefit of whole grains with quality of the baked good, is a mix of two cups white rice flour and one cup brown rice flour.