This is the basic flour mix I use for nearly all my baking. I have used it as a direct substitute for wheat flour (adding some xanthan gum, of course) in many recipes with pretty decent success. I find the key to using this flour is that you need to put some energy into it. Many recipes that I would mix with a spoon or whisk using wheat flour need the energy of an electric mixer using this flour. This flour should be stored in the refrigerator or freezer and you’ll need to add the appropriate amount of xanthan or guar gum, depending on what you are baking. I find that the high protein content of these flour mixes allows me to cut back on the gum from the recommended amount.
All-Purpose Flour Mix
192 g (1 cup) potato starch
120 g (1 cup) tapioca flour
110 g (2/3 cup) light buckwheat flour
37 g (1/3 cup) soy flour
14 g (1 Tbsp) potato flour
For each cup of all-purpose flour called for the recipe, use 158 g of this all-purpose flour mix plus appropriate amount of xanthan gum