1 cup white rice flour
1/2 cup brown rice flour
1/2 cup arrowroot
6 tbsp tapioca starch
6 tbsp potato starch flour
1/2 tsp salt
1 tsp xanthan gum
1 tsp baking powder
1 cup (2 sticks) butter, cut into 1/2-inch pieces
Combine flours, arrowroot, tapioca starch, potato starch flour, salt, xanthan gum and baking powder.
Cut in butter.
Slowly drizzle in 1/2 to 1 tablespoon ice water.
Wrap dough in plastic wrap and refrigerate for 2 hours or overnight.