Any tips for making this GF? I have that one dairy and gluten allergy guest and these would be great if it is possible!

My non-specific answer: try just swapping the regular flour for AP gluten-free flour. My favorite it the Trader Joe's brand, but Bob's or any other brand will probably work. If you have the time, I would maybe make a half batch beforehand to make sure that the swap will work.

If you'd rather not take the chances, this is a fantastic recipe that my family, even the non-GF members, love: http://www.epicurious.com/recipes/food/views/flourless-chocolate-walnut-cookies-350890 It is also dairy free.

Best of luck with your celebration!