Help with GF sugar cookies!!!!

[bright_eyes]

I wanted to make gluten free sugar cookies in the morning but am having a hard time finding a recipe.  I am new to gluten free baking.  In my kitchen I have, brown and white rice flours, aramanth flour, sorghum flour, millet flour, buckwheat flour, arrowroot starch, and potato starch.

Every recipe I have I am missing an ingredient!!!!  I have no vehicle tomorrow to go pick up anything and tomorrow is my only day before Christmas that I can make them.  The most common thing I keep finding in recipes in tapioca starch.  Can I just use arrowroot?  Why is tapioca starch so popular?  It is the most common starch I am seeing in gf recipes.  I find recipes that ask for superfine rice flour, which I don't have.  And a recipe that asks for sweet rice flour, but I only have white rice flour.

Help please!  I am so tired of searching the internet for a recipe that I have all the ingredients for.  Can someone here give me one or tell me about the tapioca starch thing (what I can replace it with).

Thanks!

[catnip]

I've used potato and tapioca interchangeably.

[ameliabedelia]

Yes, you can use potato and tapioca interchangably.  You can also use cornstarch instead.

You can basically take any regular cookie recipe and swap out the flour for a 1:1:1 mixture of white rice flour/sorghum flour/starch (either potato, tapioca or cornstarch) and 1 tsp xanthum gum.

Millet flour, amaranth flour and buckwheat flour are better for breads/pancakes/waffles...not so good for cookies. 

Rice flour, sorghum flour, potato, arrowroot are all good for cookies.