The effect of fat type, dough temperature, mixing method, baking time, and percentage flour content on texture, thickness, and taste in gluten free cookies.

 If the onerous title sounds a trifle scientific, that was the point.  We've been having an enforced snow-cation the last couple days and I was out of cookies, so I whipped up a couple batches and thought I'd play with a few variables to see what actually makes a difference in gf cookies.  I used the same recipe but varied some of the variables to see what would happen: oil vs plant butter, room temperature dough vs. refrigerated dough, cream the fat/sugar or just mix it until combined, a slightly sticky dough or a stiff, dry dough, and varying the length of time in the oven.  I ended up with about eight different experimental doughs and baked them in various combinations and carefully assessed the results, which were interesting.

I discovered that chilling the dough does nothing for gf cookies using 100% oat flour and a little xanthin gum (along with real sugar and eggs).  Neither does creaming the butter/sugar.  I used oil in half the dough and plant butter in the rest, to see if that made a difference.  The cookies were a bit thicker with the solid fat (could also use coconut oil, lard, shortening, or real butter) but I found the taste less pleasing for some reason (though I have been using canola oil for my cookies lately so it may just be a personal thing in this case) whereas the oil cookies tended to spread more and were a little thinner.  Liquid vegetable oil is a lot cheaper than plant butter or shortening right now, hence my preference for canola oil at the moment.  I also found that under baking the cookies, no matter which dough was used, made for thinner, uglier cookies, but over baking makes them too crispy.  Adding extra oat flour made for nice looking cookies but they were a bit on the dry side.

Overall results: gf oat flour cookies can be made with oil and still achieve satisfactory results.  Chilling the dough or creaming the fat/sugar doesn't improve the end result.  Baking the cookies until they just begin to brown around the edges and crack on the top and then allowing to cool several minutes on the baking sheet give the best results.  Adding enough oat flour to make a thick, slightly sticky dough results in a chewy cookie with the appropriate texture but too much makes it dry and too little will make it run all over the baking sheet.