So I looked at the reviews for Elana Amsterdam's Gluten-Free Almond Flour Cookbook on Amazon.com, and I can't help but assume that most of them are payed for sockpuppets, because from what I know about baking, only most of the negatives can be right. And I don't mean the complaints about higher than usually priced ingredients, that comes with the gluten-free baking territory, so you either buy them or don't, or at least, you know of some good companies online or off that sell them in bulk.
No, it's the complaints about oily results, and this is what you get when you use an oil in place of a solid fat regardless of what you are baking, and using a liquid sweetener, especially for cookies, really doesn't help either. It's basic baking chemistry, using ingredients that are liquid at room temperature will not give the results solid fats and granulated and/or dry sweeteners can, thus I question how much knowledge she has about wheat based baking in the first place, and believe me, at least having some grounding in that tradition helps you out even if you don't eat those products, because knowledge of baking chemistry is so important for better results. At the very least, buy a copy of Professional Baking (it doesn't even have to be the latest edition),and read it, it discuss the basic but very important things in there-even though it might not be perfectly edited.
On a side note about the agave nectar, I am surprised by the lack of complaints about how sweet the end results are, because I have had it in coffee before. Too easy to make a drink too sugary, especially if its flavored, not something I'd ever want to bother again, much less bake with. Especially drop cookies-and not I'm saying drop cooking because there are some varieties of cookies of out there that can do well with using liquid sweeteners and fats, just not ones like chocolate chip. Does Amsterdand understand these differences between varieties? I really doubt it. (In fact I was floored by one of the cake recipes, how one put a cup and 1/2 in there without hurting someone's teeth?).
I plan on eventually writing a more long winded piece about baking and substitutions someday, either here or in a different blog, but to keep things short in simple for now-
Solid items need solid substitutes. If you can't use butter, use something like coconut oil, Spectrum Organics palm oil (it's the only mass sold ethically harvested one I know of), lard, and other animal fats.
Powdery items like sugar-for the love of God, please avoid substituting it for liquid unless you know what you are doing. I have yet to try out palm and coconut sugar, but they certainly look like better options than agava and honey. If you want a honey (or other kind of cake traditionally made with liquid sugars) cake, please look for other honey cake recipes beforehand.